Got a very strange problem with a outlook 2010 client that's connected to exchange. When assigning a categorie, the sendername changes to the current owner and the email message will move to the top as if it was recently receive (inbox sorted by date, most recent on top). As if the date changes for that email message.

-tried it in the user OWA, no problems found.

-tried in outlook on a archive, no problems found

-mounted the same  mailbox on another pc, same problem

-mounted my own mailbox on the pc that's having issues with outlook, no problems found

-Checked the rules, no rules found except the default one

-Checked categories, nothing has been changed

-Created a new mail profile, same problem 

It seems to relate to her mailbox. When using OWA and assigning categories it works without any issues. It only happens when using Outlook, and it doesn't matter on which pc.

Anyone encountered this problem?