Sorry you ran into issue with your PBB. I have only heard of two instances of herm with that cross, yours being the second.got single seeds all over the place, too much stray pollen at times^^
about the Mulanje cleanup, unfortunately my PBB line is also affected by the herming.
Got a small separate tent with males and future seed mothers on a flowering cycle, had some light leak there and the PBB mother next to it ended up reversing to full pollensacks.
Saw it today, gonna make some pics tomorrow, it's the original seedling mother about 6 month old.
It took until now under various stresses to show the flaw, gonna cull that pheno of course
always treating my breeding plants like crap, some redundant clones I just let die in passive light, small pots and constant dry out/overwatering.
The stress flowering usually exposes flaws or lack there off, like good clone phenos that basically never stress flower.
But I know it doesn't make you feel any better if you are the one with the problem.
Hope you get something out of your work.