The trim pot is usually active more near 1:00 did you try to dial it in by ear?
I have never had one work set at 12:00 exactly.
Some of the intermittence errors sound like cold solder joints so I would re-flow the entire project including all off-board wiring as well.
If any of the above doesn’t help where did you get your MN3007? If you got it from Musikding you should be fine but if you got it from eBay it is probably a fake.