Can you roll a 20 (or even a 19) in the game ?

Did you have advantage / disadvantage on these rolls? It affects the results dramatically.

Having said that, my personal impression is that the game somehow "balances" the rolls based on how efficient my party is. The better I play, the more misses my characters make, cleric in particular. Same with the damage rolls, wizard regularly rolls 2 on 2d10 Firebolt, but getting 20? Good luck with that, I don't think I've ever seen it.

And no, I don't use "Karmic Dice" option.

The RNG does indeed seem broken. I've noticed similar results as OP. I also know what Rivfader means about feeling the game adjusts my rolls based on my party strength. Enemies with disadvantage have no problem getting critical hits, meanwhile my team with advantage seems to roll 2's an awful lot in the log (I wish they showed those rolls instead of just giving the result. part of me thinks it's not correctly rolling advantage/disadvantage).

Nothing quite like blasting off your only 2nd level spell slot on Scorching Ray to have all 3 roll 5 or less....every. single. time to really make you feel like you're having a good time.

Check the settings, make sure that the dice rolls are set to "True random"

Also, depending on the difficulty, you may get a minus modifer to your dice roll, also in the setting

Ten dollars says you maxed out your primary stats at character creation and had an optimized combat strategy.

So I have noticed the same thing and I think I may have also puzzled out why but its just a theory. I noticed I too was also getting a lot of low rolls but since they weren't resulting in party wipes I largely ignored it until late game where I noticed the discrepancy widened severely with my dice averaging below six and enemies between 18 and 20. This hurt because it meant I would usually receive a crit every third or fourth attack like clockwork.

I suspect instead of using any sort of real RNG, they have a system which tries to deliver mean and median results. So you hit on average and deliver average damage (check the results of your sneak attack once you have 5d6 and you will see the results are frequently 1-6 without much variation with a single number missing in the sequence for lack of the sixth die, or keep in mind the max damage of individuals and note how what they deal is almost always right in the middle) with rare instances of critical failures and successes. But depending upon the bonus' your characters have to attack, especially late game, in order to land your total roll plus bonii into an average result for that encounter (what is average will change from fight to fight depending upon TNs) it needs to severely nerf the roll. And when your AC is hovering around 26 the enemies need to just about crit in order to hit you with their +8 bonus. So there is always a finger on the scale trying to ensure combat is always a challenge without drifting into the extremes of too difficult or too easy -until the enemies require crits to hit you and then suddenly that is all they roll (adamantine armor saved my game from becoming a save scumming nightmare). Which them hitting reliably late game would make combat pretty serious but when they are crit'ing instead of merely hitting it makes every battle pretty tense. Which would be fine if I was unable to notice the finger on the scale. 

Honestly this was the only aspect of the game that really really annoyed me. I was deeply disappointed none of the choices mattered, like choosing not to slaughter all the sentient undead in the Dark Castle which has no impact on the game whatsoever (unless at the end fight, that dude was the Black Dragon fighting beside me but if that was the case it should have been more clear, but would explain why I had two dragons helping me take out a half dozen Soraks which seems like overkill), but I could live with it since choice and consequence no longer seem to be relevant to any RPG anymore. I honestly didn't mind the combat heavy game play although I would have appreciated more variation. I loved the fact that for the first two side quests you actually had to look around the environments to find the objectives. The sprites and voice work didn't bother me at all, I grew up in 8 bit. . .But this? The sheer artificiality of this particular mechanism made me feel as though my participation in the game was almost cosmetic. It made every encounter seem performative rather than significant.

Assuming I am even right about any of this, of course.

Well, a possible explanation is that we all use the Karmic Dice mode, even though we think we don't. Tactical might have botched something when they added this option, and now it's always on, regardless of the setting.

Sounds quite plausible to me.

I don't know if this has anything to do with it, but I have the impression that from the moment my characters reached level 10, the fighting became extremely difficult ... punishing. 

Even random encounters (during travel) became almost impossible. If I get suprised, they kill my tank in the first 2 turns before he had time to do anything (critical on critical, paralyzed, etc ...)

I was forced to switch from Cataclysm to Scavenger mode

I've never had any problem rolling 20's.  I am not using Karmic dice.  I'm playing the game on the core rules setting.  Character creation was done by assigning whatever numbers I wanted for each stat, so my guys were a bit juiced.  Didn't seem to affect die rolls at all when compared to my previous playthrough where I rolled for all my stats for all four characters.  

I also had no problems with the 20s. Everything was like a real table.

This has been my experience as well, seeing all of the typical wild swings of fate I have experienced at many face-to-face games over the years.  It is absolute normal to experience small samples where highly improbable events take place.  I recall watching a player roll three natural 18s on 3d6 in a row while playing Champions, which uses 3d6 for attack & skill resolution.  Since the chance for just one 18 is 1 in 216, the odds of rolling 3 in a row is less than 1 in 8 million.  (This was especially hilarious, since in Champions an 18 is the absolute worst roll, so his whiffs were EPIC!)

But given the millions of die rolls made by players over the course of more than 4 decades of roleplaying games, an outlier like this isn’t to be unexpected.  In fact, not experiencing small sample sizes of outrageous luck (or unluck!) is more likely to be the outlier.  If you have played games with random result generators like dice & haven’t experienced the slings of outrageous fortune, I question your recollection. 😉

I been rolling a lot of 4s, 5s, and 6s, during combat lately. My Paladin had to drink a Potion of Greater Healing. 3, 1, 1, 2. Yeah that sucked.

Cat observes. Cat sees the complainants play cataclysm and folks with normal rolls play d&d, also known as core/authentic/whatever it's called in this game in particular. cat wants to sleep because these are sleepy, trivial, almost tautological thoughts, it is self explanatory that d&d players play d&d, and when you do that - d4 means d4, d6 actually, honestly means d6 and so on. Unless cat has the blade that has eaten so much it's not dangerous to touch anymore at which point she rolls 1d8-2. Cat opened a door with that serrated longsword though, once, a long time ago. But cat can't really sleep because this is also funny because there are those others - christian crusaders problably, they really care about those plus signs on shields. So these others think it says something about their character or personal qualities if they play with an across the board -2 or even -4 on all attacks, all saves and most importantly, surprise surprise, on all dice rolls.  And ironically they are right, it does. It's nothing cat would consider flattering though.  

i hear ya, after running in scavenger mode up to the point where EA ended i still found it too easy so i decided to start over before i got to any of the new stuff but now in Cataclysm mode.  wow it is brutal.  i barely made it through those first two fights with soraks, i even had to use a Revivify scroll on that lazy robar, i wish we could give him some javelins or something so he could be more than a pin cushion.  the first fight was the hardest because i could not roll above a 8 for a long time.  i think it was the 10th round before i dropped the first sorak.  and in Cataclysm mode they can bring the pain, i had a character drop from one non-critical hit.  they had over 60 HP while all my characters had less than 20 at max.

the second fight started off great however, i had three nat 20's in the surprise round, though, it still did not drop the first sorak, then things got harder.  but that should give you perspective: in Cataclysm mode,  i could not drop a sorak with three back to back crits while they can drop me in one shot with a non-crit.

another thing, there was a sorak in the red with the HP bar barely visible, so i expended a magic missile at, three 3(d4+1) later and it was still up, then it regenerated for 16 points and dropped me on its turn.  i'm like WHAT!!!! my character started with max HP of 17 and it is regeneration 16 points and then dealing out almost as much in the same round.

another data point on Cataclysm model,  the job board mission to go back to the first sorak battle, they said be lv4, but i did it with lv3.  i'm using point buy built characters 

another data point on Cataclysm model,  the job board mission to go back to the first sorak battle, they said be lv4, but i did it with lv3.  i'm using point buy built characters 

I think that's just "recommended level" though, not the minimum level to succeed. Just that being below that puts you at a disadvantage statwise.

On the topic of the thread, the rolls do seem to have gotten very strange indeed since Early Access. I've both double and triple checked Karmatic Dice was turned off when playing because of the outcomes.