Exchange 2010/Outlook 2010 users randomly cannot open items, or mark as read/unread

We have an Exchange 2010 server that we recently (Wednesday) installed Updated Rollup 8 for SP3 on.  Since that time we have had users randomly encounter issues.  The first sign of issue is when trying to open items, we get the error message 'Cannot open item':

Nothing appears in the event log of the computer, nor the server when this happens.

We also get the error when marking as read or unread 'Cannot mark the items read or unread.  The most likely reasons are:...'
This is happening to multiple users on both XP & 7, all using Outlook 2010.  So since this seems to be pointing to the server we decided to run a database repair, which did fix errors, but users are still having issues exactly as before.

These are very random though.  A user will be able to not open an item, not mark it is read/unread, then shortly thereafter have no issues doing the exact same thing.

So now we are stumped, nothing seems to be fixing the issues, and no sign of where the errors might actually lie are being reported.