I think your problem might lie with the molasses and the length of time your particles were in the bag/mesh before being used allowing the molasses to be absorbed by the pva. Also oil based paritcles seriously affect the melt time sometimes for the pva not to melt at all, unless it states that it is pva friendly.
A few years ago i pre tied some in mesh with pellets the night before thinking i'd get ahead of the game, and as always i tested one when i got to the bank, 35 mins later it started to break down, turns out it was the oil in the pellet being absorbed into the pva over time causing the problem. So i had to make them as i needed them and they broke down almost straight away.