In no particular order (v0.5.42), sorry if these are known.
i. Magical Two-handed swords +1 add their bonus to attack and damage twice (actually lists the bonus twice in the tool tips as well).
ii. When wearing armour with a helmet a characters hair will clip through it.
iii. Bless/Guidance doesn't shown what it is adding on the tool tip when you hover over the log for a roll
you just get the total bonus (including the bless/guidance one), ability modifier and proficiency modifier, and/or cover modifier.
iv. Girdle of Hill giant Strength has the description as setting to 19 strength rather than 21
v. Gauntlets of ogre power seem to gain the racial bonus for humans (not sure about ASI, or other races), making them set Str to 20 rather than 19.