rt-ax88u wifi connection slows

[peterson65]

i have a rtx-88u it is connected to a rt-ax57 by ethernet as a mesh setup. i have a strange problem that i cannot figure out. my cell phone if its connected to the main router and i do a speed test i have a fast rate but it i try lets say hours later or overnight it went from around 400mbps to only 16. if i turn off the phone wifi and reconnect its fast again. if i bind it to the mesh router the rt-ax57 it never happens i have checked every setting i could find any ideas or is the router dying. i do have stock firmware and the latest. thanks

 

[degrub]

do you turn off your phone's connection to LTE cellular while testing ?

Also, the client ( phone in this case) determines which AP it connects to. Possible that the phone is still connecting to the main router , but a reduced bandwidth because of distance/signal level.