I recently configured three Deco M5s in a network and turned 2.4Ghz off. I do not see the M5 2.4Ghz SSID, however, wifi sniffers detect multiple hidden signals on channel 9. These are from the Deco M5s since the MACIDs start with "EA" like the main signals and I have no other devices on channel 9 - I only use 1/6/11.

How can I prevent the Deco M5s from broadcasting on the 2.4Ghz band? I have other SSIDs on 2.4Ghz and I want to prevent interference. In fact, since turning on the Deco M5s I have been seeing errors on other devices connected to other 2.4Ghz signals.