Outlook Sync CRM 2011

Hi.

We have noticed that recently, when users are going Online within outlook client, the contact date of births are getting updated with either an 11:59:00 or a 12:59:00 timestamp (rather than 23:00:00 or 00:00:00).

This has only started happening recently.

Anyone have any idea what might be the cause of this? A setting somewhere?

Thanks