I am glad to see I'm NOT the only one with this problem! Mine occurs more with repeated staccato chords - one note of a chord will stay on. This suddenly started last November as well. I sent the keyboard in, and they were out of stock on black keyboards, so they sent a white one. I'd prefer the black.
Interesting that I had my keyboard since Christmas '18 and no issues until November '19.
I tried using the keyboard on a laptop, end experienced no problems for an hour, so assumed at the time it was something to do with my desktop. It WAS pretty random, not occurring more than once and hour, but then I found a voice onmy desktop that happened too often!
Specs:
Using Analog Lab 4, DX Piano preset (Farfisa) on Keylab MkII (white) you sent me.
Windows 10, v1909. Ryzen 5 2600X, 16GB RAM, 64bit, SSD 500GB
SoundBlaster Audigy 5, ASIO4ALL, V2/14
Hope they get this figured out!
Al Schlafli