Searched, and didn't find this, so creating. It may explain some of the "Missing bees in villages" reports:
I watched a bee get "walked on" by a villager when it was flying low to the ground, a grass path block, and it flashed red and then died.
I'm not sure if it's something to do with the grass blocks being less than a full block high, or some interaction with the villager, or both.
Could you attach a video of the issue happening? If the video file size is too large, you can upload it somewhere else (p.g. YouTube) and then link to it here.