I believe it is related to not purging the dms when unfollowing, upon refollow they still exist in memory and the refollow crawling operation will end up adding extra copies of the followeees content. Havent reproduced it since I saw it but I believe this is what happened. If so, the solution should be to purge the dms from the followee out of the ordered array they are held in at the time of unfollowing.
I believe it is related to not purging the dms when unfollowing, upon refollow they still exist in memory and the refollow crawling operation will end up adding extra copies of the followeees content. Havent reproduced it since I saw it but I believe this is what happened. If so, the solution should be to purge the dms from the followee out of the ordered array they are held in at the time of unfollowing.