Do not understand "wireless status"

Hi,

I have a SG135w (UTM) and 3 AP55 in place and created a mesh NW. 1 Root Mesh AP (AP1) and 2 Mesh APs (AP2 and AP3).

Calling wireless status page I get this what causes me to get completely confused:

First line: I expected, that AP1 is unable to serve clients because it is the root AP. But line 1 shows something different.

AP2: I expect that the mesh network is 2.4 GHz and clients connect to 5 GHz? But clients connect to 2.4 GHz.

AP3: never had clients on until now (coincidence?)

In the mesh network: What does that mean? AP1 (root) has NO Mesh Peer Link)?

AP2 has a mesh peer to AP3?

I am unable to identify the peer MAC addresses shown up in AP3 as peer partner.

Is somebody there able to open my eyes?

Thanks

Gernot