RT-AC88U dissapering/disconnected 5Ghz band

[Piccolo]

Hi. I'm back with a new topic, namely I have RT-AC88U connected in a mesh (with a cable) together with RT-AC68U. Since the last 2-3 versions of MerlinWRT, something has been happening that randomly disconnects devices from the 5Ghz network - it happens randomly, at very different times. Most often, you cannot connect to this network again because the device does not see it - it only sees the network from the second RT-AC68U router (of course with the worst signal) The only thing I found in the logs was that the device was suddenly disconnected. Just reboot RT-AC88U and everything returns to normal. It's no less annoying