I have contacted Adam Pryor in tech support about this because mine straight out of the box new had this issue.
We verified that Firmware version 1.8 was in the unit successfully and even reloaded it successfully without any change to the issue.
My particular symptom was I had a sub oscillator clicking noise after I initiated the function and pressed a key, not no sound completely like some of you have stated. I then had no Oscillator control after that either.
Here is a video clip I sent to tech support demonstrating the problem I had with my unit:
https://youtu.be/qr6H9NN_DJYThey had a unit on the bench that did exactly the same thing. As of now, all we can do as Minimoog Reissue Owner's, is wait for the next version of Firmware that will fix this problem and upload it when it is available if you want this turn on function to work.
If you have a minimoog reissue to where this function works, then you are lucky. I will keep all of you posted via this forum if the next firmware version works as I will be receiving Beta test versions to see if it will work in my unit.