Since I started animating using referenced rigs in Maya, I have had a problem with animation curves randomly disappearing. I would be animating away, and all of a sudden, an IK foot, for example, would stay behind where it was at its bind pose when opening the project. Extremely annoying and time wasting, and almost defeats the purpose of referencing in the first place. Saving incrementally only partially works, because while you are animating, you can't see when a node disconnects, so it will look fine until you close the project and reopen it.
Today I pretty much confirmed that Maya is disconnecting certain nodes at random, as I referenced one of my own rigs and one joint would not move with its controller at all. When I imported another identical one, that one worked. This is unacceptable.
What is causing this, and is there a way to fix it, let alone prevent it from ever happening?