Last night I was testing out the regen on the gear I had. So I spammed Bombard (Arrow Spray) to use up some stamina and then watch the regen. My regen was a little over 1800. After a few Shots my stamina was down about 30% and then didn't regen for about 20 seconds. When I checked my character sheet it showed 0 regen. After doing a dodge roll it went back to 1800 and started regenerating.
I didn't look into the bug more, but wanted to bring it up in case others have seen something similar.