Ikea trådfri power outlet spontaneously leaves Zigbee network

Had over … 4 or 5 those outlets and never happened to me - I have another problem, that 3 out of 5 were already returned within warranty period.

Anyway, it would help to submit your mesh network from https://tools.developer.homey.app/tools/zigbee

You may also consider running this script (it might give you some advices) - [Community Survey] Homey v5 ZigBee Health check and statistics collection (HomeyScript)