Deleting Version and data Source connection

I'm wondering if anyone else has had this problem. When deleting a child version out of arcmap(ArcGIS 10.0) and opening the map the following day all of the data source connections have been lost and the data needs to be resourced. I've noticed this seems to happen when the version is deleted from a different mxd then it was created in. I didn't think versions were related to the mxd only the database itself. Is this incorrect?

Thanks for any assistance,
S