Mecanim "Any State" transitions keep disappearing

Having an interesting little problem intermittently here in version 4.3. Every so often, I will open up my project and find that every transition from "Any State" to anything else in Mecanim is gone. I haven't touched those transitions in a while and I'm save-obsessive, so it's not like I'm forgetting to save my changes. Each time this happens, I re-create them from scratch and they'll be gone again in about a week.

Any thoughts? I'm admittedly stumped. =)