Here at Qualcomm, we have experienced the following issue with Project Professional client (both 2010 and now 2013) where the client cache is out of sync –
User published and check-in the project from client, and later on trying to open the plan again for editing. This time, the plan is still showing with “Check In Pending” in the client. However, the server is showing that the plan has successfully checked in, and no other users have checked out the same plan.
At this time, the only way for the user to edit the same plan is by clearing out the local client cache via OPTIONS>SAVE>CLEAN UP CACHE.
Does anyone knows more on how client cache is managed in Project Server/Project Professional?