I appreciate your help. I posted more details about my system above (we were apparently posting at the same time), but because others have posted about this same issue with the AXE16000, I'm fairly convinced it's a software issue...
GT-AXE16000 as main router. Merlin 3006.102.4.
I have another ASUS router (RT-AX88U PRO) set as the mesh node. All was good under the prior firmware (Merlin 3004.388.8_4).
But under 3006, the SSID on the mesh node for both the 2.4GHz and 5 GHx band are the same. That is, should be ASUS10...
There's a bug (I think carried over from ASUS firmware) that affects AI nodes. The 5Ghz band duplicates the 2.4Ghz band SSID on the node, instead of using the same SSID on for 5Ghz on the main router.
I have the same issue. AXE16000 as main router, AX6000 as node.
The node is assigned the same SSID on both the 2.4 and 5, even though the main router has different SSIDs.
It is a problem because everything on my network is mapped to the SSI for the 5GHz band.