Long story short, I have 4 Deco M5 units in the house. 3 of them work fantastic but I have one that is plugged in directly with cable that runs in the basement to the other side of the house.  The device it's plugged into is rock solid all the time, however when my phone connects to that deco, it seems to not have internet for at least a few minutes if not longer. 

Eventually it gets internet but often I find myself just disconnecting wifi and using my data on my phone to do something when I'm on that side of the house because I know when it stalls, I'm connected to that puck. 

Has anyone else run into an issue similar to this?  I also have alerts setup when devices connect to our wifi and for testing purposes I left an old phone in that room with the deco that is problematic and a few times a day I get an alert that my phone has connected to the wifi. 

It's really frustrating and I'm hoping there might be a fix for this.  It's just the wifi, because the hard wired device that is plugged into the deco works perfectly 100% of the time. 

Hopefully someone has some suggestions on what can be done to fix this.  

Fast roaming and beamforming is disabled and I've tried both.