wow herm is supposed to be due to stress but more and more ppl are having problems.
i think you should contact dutch passion and see what they say.
Any feminized seeds, from any breeder, does have a slightly higher chance of turning hermi than regular seeds. That is the risk/price that you accept when you purchase feminized seeds.
Some strains are naturally more prone to turning hermi and when you purchase those strains in feminized seeds the chance of occurrence of hermies increases. When you use such strains you need to be quadruply careful to not allow or cause any stresses of any type, from root-bound conditions to how they are fed to heat stress to light leaks and any and every other possible source of stress. You need optimal conditions from start to finish to avoid problems. Dutch Passion Blueberry is not a strain for beginners or growers with less than optimal setups or for lazy growers. Odd/unusual leaf growth/shapes are also common.
The same basic problems go with any Blueberry strain from any breeder, and to some extent any cross from any breeder that is a cross with Blueberry in it.
Blueberry is great to smoke but it can be more than just a bit finicky to grow and that is less the fault of any one breeder, or breeders, as in them not being proficient at creating and maintaining optimal conditions for growing their seed producing females of the actual creation of their strain or seeds, than it is the combination of strains that are needed to create the strain.
Somewhere in the lineage chain of strains that were over time combined and used to create Blueberry the hermi trait existed to a fairly dominant degree and has been passed on. It may have come from even just a single chosen phenotype that was used at some point, but wherever it began it has been passed on.
Dutch Passion - Blueberry
DJ Short- Blueberry
Somewhere in those lineage chains an unwanted hermi trait existed and it is one that was/is dominant enough to be passed on and remain dominant. Some Thai strains have been known to be hermi prone so if I were to place a bet on where it all began that is where my money would be placed, but again it might have been just a chosen phenotype that was not at the time known to be hermi prone or known to be hermi prone but believed to be of a low enough rate of turning that to get what was wanted from the phenotype it was seen as being worth the possible risk/costs of using it.
But that is only my personal assumption.