All Yeelights turn on and become unresponsive at the same time

I have 4 Ceiling Lights and 3 Color Bulbs (2 versions). They are connected to a 2.4 Ghz network using a TP-Link EAP245 v1 access point, using a dedicated IoT SSID (for a IoT VLAN). An EdgeRouter X SFP controls my network.

At random intervals (approx. once a week), all 7 lights turn on at full brightness. They flash (briefly decrease and increase brightness) at a low frequency in that state. I cannot control them using the app or using Home Assistant (which uses the python-yeelight library). I can connect to my access point, even to the IoT SSID and browse the internet.

All lights (and the access point) have the latest firmware (1.5.9_0184, 1.4.2_0035 and 1.4.2_0070)

I have disabled all the firewall rules for the IoT VLAN to make sure that isn’t the problem. Power cycling my access points causes the ceiling lights to respond again; the bulbs need to be power cycled before they respond again.

Given the fact that it concerns all lights at the same time, it must have something to do with my particular setup, but I can’t figure out what.

Does anybody know in which (connectivity?) circumstances the lamps enter the ‘full brightness and low frequency blink’ mode? That might be the start to correcting this issue.

My ID is 1632835803

Your mobile phone must be in same network!