So after finally being able to register my Minibrute (my fault, I was entering the serial number incorrectly) and receiving the technote for the service manual, my local synth tweaker was able to properly tune the synth using the slope trimmer controls.
It was his opinion that the synth was never tuned properly before leaving the factory, as it took quite a while to do using a frequency counter and a multimeter (but that's just one man's opinion).
Still quite curious that although it was out of tune, the unit couldn't stabilize on a note whatsoever but the problem appears to be remedied.
I've taken down the youtube video as well.