Have you noticed task names disappearing from your schedules in Project Server 2010?  Well according to Microsoft, they have found a repro and it appears related to multi level undo.  They are working on a fix and (no promises) hope to get this in the next client side Cumulative Update in August.  For now if you are hitting this a lot then turning off multi level undo is certainly one option.

This was from Brian Smith

http://social.technet.microsoft.com/Forums/en-US/projserv2010setup/thread/8fc742d9-3909-4cb8-afd3-9d29967464e3#f432f54b-a0c5-46d5-82b5-fc5b6cc4f45f