I have a few months old Rytm with what looks like a small dot made with a black pen on the inside of the glass like it is above the LCD. I have not turned it on for two weeks and it was in the box with protective cover on the entire time and when i turned it on today it was there. It is still there when i turn it off. No biggie but mildly annoying which is a shame on such a fine (and expensive) instrument.
I guess it’s kind of dust grain i have that on my Analog Four freshly buy … but it doesn’t get the A4 from working so i keep it like that. it’s hand made 
It’s easily removable but opening the case will void its guarantee.
Thanks for the reply. I figured it was some dirt but just wanted to make sure.
Try removing encoder A or the Level encoder knob and use some compressed air.
Be sure to use compressed air!!!
It’s analog … VCO 