Devices attaching to backhaul channel

[Hardreef]

Looking for some advice here. Have an AiMesh network set up with a GT-AX 11000 as the router and RT-AX88U as an access point. Both routers have the latest firmware. Setup was pretty easy with no real issues. Since the Primary router is a tri-band, AiMesh set up the 5ghz gaming band as a dedicated backhaul channel (or so the software tells me) but I still have devices attaching to this network. Is that normal or is there something wrong with my setup?
Thanks in advance for any recommendations.

 

[Grisu]

They could be connected to child router 5G.

 

[Hardreef]

I actually returned the AX because it began dropping both the 2.4 and 5 ghz networks. Fingers crossed that the AX11000 continues to work well.