Hi, 

Network topology:

                                         - Deco AP 1

                                         |

Modem  -- Asus router ----- Deco AP 2

                                         |

                                          - Deco AP 3

Problem: 

The APs are wired as such. When I first start to use them, all APs show "Ethernet" as the connection mode to the main router. However, after some time, some Decos will start to switch from ethernet mode to wireless mode, in which these Decos get connected to other decos wirelessly. Then the speed will drop drastically. Can confirm through speedtests that the Decos are able to be connected to the router via ethernet backhaul.

All Decos are on the latest firmware

Is there any way to solve this? Thanks!