Expression not updating

I have a file in Maya 3 with around 20 expressions that don't update. Expressions are enabled and the expressions are correct. When I open the expression editor and hit the edit button for each one, the expressions begin to work fine. Till I save the file, close it and open it again. Then they're back to not working.

This is probably some kind of bug in the file, but has anyone seen this before and perhaps found a workaround.

Ragnar