I have bought Deco XE75 3 Unit Mesh system around 6 months ago. I have configured one unit as the main unit and two units as satellite units using WiFi6E for backhaul. For 6 months the whole system had been working beautifully. But in the last few days, _one_ of the satellite units (named "Master Bedroom") keeps disconnecting from the main unit (named "Living Room") (Solid green LED changes to blinking Red LED). If I turn it off and turn it back on, it connects to the main unit and the LED turns Green, but within few minutes it disconnects again and Red LED starts flashing again. I tried keeping the satellite unit right next to the main deco unit. I tried to remove the unit from the mesh, reset, and add it back to the mesh. I see the same behavior.  In fact, it did not add until connected it to the main unit using an ethernet cable. The second satellite unit (named "First Floor") has no problem connecting to main unit over 6E backhaul.

However, when I use wired ethernet backhaul, this satellite unit works just fine. I suspect that this unit has developed a problem with 6E, and I need to replace this unit. Is my diagnosis correct?