Dj short invented/created the blueberry by crossing two landrace strains.. When you cross a landrace with another landrace you are bound to get herms here and there throughout the generations. Same thing when you cross a chem with a chem or a cookie with a cookie. Some strains are very sensitive to environment and crossing them often brings that trait forward. The issue appears a lot less at f5 than it did at f3.. The slightest changes in the environment would stress them and cause them to herm. There are a handful of photo period strains that are know to herm because of the parental lineage.Watch carefully... Blueberry is well known for herms... it's just the Gene's, but its there... so, smooth runs, no light leaks etc. Sometimes they just pop up too so eye out for sacks and nanners. Ran it a long ways back, but I was in a group that started 50 plants and ended with one mom between us all. Never had a nanner or sack from her or her cuts. Several of the discarded plants were tossed due to hermaphroditic issues.