I would suggest aborting any WUs that are still using the old app versions. There's a small bug in the older versions that can cause some WUs to get "stuck" after restarting from a check-point. This was only affecting the windows version. The newer apps have been out for over a week, but some users have a large work queue, and may not have picked up the newer versions.

Here are the latest app versions:
GD: 2.07
GBD: 3.05