Suddenly the connection is back
Check and see if your thread network is on the same channel as your Hue network. If they are, change the Hue channel and see what happens. I have been having periodic device drops. When I ran Thread Doctor, a number of them had very weak connections despite the fact that they were very close to a border router. Once I changed my Hue network from channel 25, the devices all came back online
Maybe this upcoming change will be helpful in identifying and resolving Matter-over-Thread issues:
