I have the same problem with all 3 ceiling lights since the last firmware update (1.5.5_0181).
They all drop off WiFi many times per day (probably over 20). One dropped off permanently today, so I had to turn on/off wall switch in order to get it back online.
They worked flawlessly for the past 4-5 months and haven’t changed anything else on my side (same router, AP - Ubiquity pro).
I talked with few other users that have same issues since the last update so it must be software/firmware related.
Some parameter change were introduced in 1.5.5_0181 to adjust WiFi power saving mode. This issue could be one of the side effects (not detected in our lab test environment, could be compatibility issue)… A new version to rollback the change is in beta now. Available once your MI ID is in the white list.
BTW, we also fixed some WiFi defects which may cause the device to go offline. The official release will be ready in a couple of weeks. Please stay tuned.
Than you for the update but it didnt resolved another problem - I cannot control Bedside Lamp via HomeAssistant. Maybe LAN mode is disabled by default in MiHomeApp plugin?
Can you turn it on by default like before?