So I'm not sure WHEN this bug was introduced, but it wasn't always there, at least to my knowledge, I know it first started popping up when grubs were introduced around that time, but basically whenever you use an herb bag on a bag filled with herbs, there is a small chance that you just lose the entire herb bag contents.
Like for example, I had 12/20 bleak caps...
It consume all the bleak caps in a bag...
and the herb bag is now empty at 0/20.
It's really inconsistent on when it works out, and I can't replicate it, but I've lost somewhere in the vein of around 140 herbs to this damn bug. It's very hard to sort of provide evidence for this, but it does happen, erratically, it ussually happenswith bags that are over 10 full trying to pull from bags, but I've had it happen trying to put herbs into other containers too.