Signal strength changing intermittently

This is happening on only one CPE, on a 2.4Ghz, nv2 network, with Metal 2HSPn router.
I have done a fresh NetInstall and upgraded to the latest RouterOS.
The rx signal strength changes intermittently. Can anyone point me in the right direction, to get this fixed?
Metal 2SHPn.PNG
Metal 2SHPn b.PNG