Shared Groups sync error message

[Caitlin]

Dear Daniel,

Our shared groups sync just recently started displaying this message: Fatal exception while processing [username], skipping this user. Internal reason: [Line 86, Column 55, element app:edited] Invalid date/time format: 'null'.    This message started appearing this evening as I was working on making all users read only and then giving my admin acct editing capability (so as to work on merging contacts).  I saw that another poster had a similar error message and you replied it was a bug with Google.  Is this the case for my error message, or do you think I triggered something with the work I was doing?  Are contacts still syncing through when this error appears?  Can I disregard the error?

Best,

Caitlin