Wattbike Atom - downshifts to first gear and won't shift out

I have been using my wattbike atom with zwift for about two months. I have a recurring problem every time I ride. When using high amounts of power (usually when standing up or going downhill), the gearing will all of sudden shift down to first gear and won’t shift out of first gear. This happens a few times a ride. I usually have to wait a minute or two before it will start to allow shifting again, although sometimes it won’t allow shifting at all and I have to end the ride. I see some references to this problem in other posts, but no apparent solution?

Make sure that the rubber cover over the gear selectors hasn’t moved. This happened on my Atom not long after I’d got it and what it was doing was rubbing against the downshift button, meaning it was constantly sending me down one gear every second; even if I shifted up manually, it would counter it and shift back down almost immediately. Taking off the cover and re-positioning it seemed to fix the problem.

That seems to be the problem - thanks!