Issue with new firmware on R5- Ibis shivers permanently

Dear Photographers!
Back after an long recovery from iatrogenic caused problems, I´ve updated my R5 to the newest firmware. But I see strange behaviour when I switch on Ibis-Pixelshift. Then Ibis starks shivering (like when you clean the sensor). If you press the shutter, no shot is taken. I repeated the FW update several times, but nothing changes. No other issues recognisable.
Any thoughts to correct this? Here, Canon CPS increased it´s prices heavily and no cleaning is for free anymore.

Thank you very much!