I was testing out an encounter in the dungeon maker with a level 5 party.
My cleric had spirit guardians up and managed to roll a 33 damage spirit guardian roll.
For some reason it rolled 9d8 damage dice instead of the 3d8 it should have.
Here's a screenshot of the issue: https://imgur.com/a/WBgZZh6
It may be because right before that my Shock Arcanist cast fireball and got 33 damage on that roll (maybe it's re-used the same roll accidentally?).
All other times spirit guardians seemed to do the correct 3d8 damage.