@Greg_B In my case, I donot have a M5. All 4 units I have are X90's. Also connection problem started happening after 09/2022 firmware update. Its now getting worse as my IOT devices keep loosing...

Having the same issue after updating to 1.1.3 Build 20220927 Rel. 50772. I have 4 deco x90's: total 4 APs (1 primary, 2 connected to primary via ethernet and the 3rd connected over wifi).