I recently started to get the “The Ethernet Backhaul speed is low” message in the Deco app on 2 of my satellites. This message wasn't there before and started only recently. 
 

I also have an M9 Plus satellite that does NOT have this message. 

My internet speed is fine (900Mbps+) - confirmed via speed test when connecting wirelessly and wired. 
 

Other things I tried / confirmed:

* restarting deco devices

* cables and connections are all Cat 5e or 6

* cable connections are secure

* restarting switches in between the main and satellites - error message goes away temporarily but then returns

* latest firmware is installed

I can't tell if this is a false positive or real issue given my tests.  Either way, I'd like it fully resolved so I can rule out even potential issues. 
 

As an aside, I did not receive any notifications when this message started appearing, despite device alters being turned on - if I had it may have been easier to diagnose since if some event (power outage, firmware update) had caused it, it would have been easier to correlate to that event.