Flying critters are getting stuck in liquids and never fly out again. Examining their pathing shows they can move out but they never do. I tried deleting the water pump but that didn't work. The shine bugs were actually stuck in the water before I built any of the mesh tiles and they just flew back and forth along the top of the water.
Steps to Reproduce
There isn't anything in particular you can do to reproduce this, although allowing the egg of a flying critter to hatch underwater might do the job. In my case, the critters simply flew into the water and stayed there.
This issue has not been confirmed by a developer yet.