We have an issue where periodically (monthly it seems) some users will lose specifically granted 'contribute' permissions to certain subsites in our SharePoint environment. I did some research and found one blog that suggested the culprit could be 'duplicate' user entries in the UserInfo table of the content database. The profile import/timer job, the blog claims, does some sort of housekeeping which then removes all of the user's permissions, due to the 'deleted' record.
I looked in our UserInfo table and I see that the two users I have problems with do have duplicate records for the same site, however one record is marked as deleted and not active and the other is marked as active and not deleted. From what I have read elsewhere, that should be just fine, so I hesitate to write an app to delete the 'deleted' record. I was hoping to find a more definitive answer to this question before we go mucking around with the data.