This is my setup:
2 ASUS ZenWiFi XT8 nodes in AP mode with split SSID for the 2.4 and 5GHz channels (was a requirement to be able to connect my SONOS One SL), connected directly to my ISP modem/router.
Firmware version 3.0.0.4.388_21099.
All devices are able to connect without issues to both...