@norbert_pdm 

The Wireless WiFi type icon beside connected indicates these are connected via MESH (WiFi) and not over the LAN connection.   It could be there is a cabling issue for those devices, check its LAN connection back to the controller.

If you dont use MESH you can disable it via the SETTINGS > SITE > ADVANCED SETTINGS and that will stop any APs connecting via Mesh.  However should they not have a LAN connection they will go offline instead.

Yes Mesh will be slower than a LAN connection, its basically AP to AP via WiFi. 

  @norbert_pdm  Hopefully this helps a little. In the first image below, the Main AP that is wired to the router / modem is at the bottom of the list.  All of the other APs are connected wirelessly to the main AP. Also each of those APs can connect (HOP) through each other wirelessly back to the main AP.  I learned that dealing with switches, POE or not, depending on what else you have connected on the switch, an EAP connected to that switch could be detected as wired. If you provide an actual schematic of your network it would be easier to understand if there are any issues.

In the diagram below, the EAP225 Outdoor would be detected as wired because the main up-link to the Wired EAP610 Outdoor is through the CPE710.