It's not the most common bug but it happens now and then. Seems to be an issue with the game getting confused at whether or not you are allowed to cast the spell. Happens when ally is sort of LOS sort of not LOS.
I don't think the armor piercing rounds does anything special besides let you ignore bullet res
I don't think there is a bug, as far as my testing in test lobby goes
I think it's just phantom strike --> punch --> express shot hit = tons of dmg in one combo
I was just about to post this topic myself when the forum auto suggested this topic to me. It seems like this line of tiles in the back of the pit is what separates "the pit" from "outside the pit". I assume that the patron got moved at some point and so it is using old boundaries instead of...
This bug is still happening. Enemies keep reappearing in locations other than where the ult preview shows. Easily replicate-able with any sort of movement effect or ability, even "fast run speed", "dash", "jumping", etc...