I'm having an issue where when I try to assign permissions to some users I get the error message, 'Multiple Entries Matched, Please Resolve' If I click to resolve the issue, only one user is displayed and the error message won't go away. This happens only in the Production environment, the users can be resolved in the other environments. The strangest part is it only happens on certain sites, it seems to be isolated to one of the content databases, I'm able to assign the users permissions on sites which live in the other content databases. My first thought was an issue with the AD User Profile Sync but everything checks out when comparing the working environments to the non-working environment and the fact that it only happens on one content database makes me think it's not a problem with the sync. Any suggestions on what this could be or what paths I could take to debug it? I've tried everything I can think of.
Thanks!