MR52 5g rx help

I have posted a couple of times regarding my problem with a Meraki MR52 5g radio.
Having tested some more, the 5g radio seems not to be able to receive. 'Channel analysis' and 'scan' for this radio show nothing (other than the same 5g radio if an SSID is enabled). Tx seems OK as wifi clients and other APs can see it, and the signal is good.
The same unit's acbgn radio seems to RX 5g OK as it can see nearby 5g APs.

I have visibly checked the 5g pigtails and their solder connections to the internal antennae. They seem secure. Is there anything else I might try? Or is it looking like this units 5g radio may be broken?
Any suggestions much appreciated.