Interesting 🤔. Is that when logging in to your profile, though? I've had my Quest 3 for 7-8 months and always had the grey dotted screen. Do you have Navigator? Maybe that's a Navigator feature🤔? I don't have Navigator yet, been waiting forever for it.
Btw, after getting the stable 2.1.1034 update (build 5194302.5050.520 on 27 Feb) on my Quest 3, I still had the grey dotted background after restarting the headset. Then I fully powered it off and back on again, and now I have a new profile menu screen with passthrough background, a virtual "+" button on the right to add new profiles, and a virtual power button underneath 🙂.