I have this problem lately,
in one of my tracks I use a “bell” sound that does not come from the oscillators but from the second filter (resonance full up).
I was able to play it harmonically but suddenly when powering on the A4, it didn’t sounded in KEY anymore.
I have a difficult time now to adjust in so the melody sounds in key. What ever I try (frequentie or track) parameter I choose. I cant get to the sound I had before!
Anyone some advice?
IT has to sound like this https://www.youtube.com/watch?v=SW1Ls59BE44&t=1361s but whatever I do It does not sound harmonically like this anymore 
Tracking both at 32, frequencie tuned with a tuner … not correct
How long are you leaving the unit powered on before you attempt this?
Long enough 
believe me, I discovered that the tracking was originally not on 32 but around 28, still searching the correct spot (really strange why it sounded so good then :d)
I have the same issue with filter one. You can try to do the calibration procedure.
I would be intrested if the first filter is capable of a stable tuning by value 32 filter tracking.