What's happening here is that there's another bug that I've had to fix by making it so they don't pick up more than half their maximum weight at a time (it's a long story, but trust me). As far as I can tell on my server, that's probably what's happening.

So, will you be able to fix it or is it intentional?

It also looks like they stop working if you enclose them in a small area (2x3).

Dung beetles are bugs! D:

Just thought I'd say something random and potentially funny. :|