Yeah, that DRS thing seems like a bug - pretty sure 5e doesn't work like that. So another bit of lazy coding on Larian's part. There is no way bonus damage (from feat or anything else) should trigger some other conditional damage affect as if it were a separate damage source. If you smack someone, it's one weapon attack - that gets appropriate bonuses (including from feats, abilities etc) . Your second (or later) attacks can provide 1 damage source each.
This stuff makes my eyes bleed.
PS 5e is full of limits like this e.g. rogue sneak attack affects only 1 attack per turn (even if you attack multiple times, and the same conditions hold). They considered these kinds of stacking behaviors carefully to avoid balance issues. Another reason for Larian to have a proper 5e mode - sure most 'egregious' abuses would vanish with that.
Last edited by booboo; 20/11/23 05:51 PM.