Asus RT-AC58U Router randomly stops providing internet over ethernet while WiFi works w/o problems

[adwil13]

For a week or so my Asus Router started to misbehave. It stops providing interneto over LAN ports for some reason.
All I have to do to make it work is disconnect and reconnect all LAN cables (WAN too).
While problem is happening all computers connected over ethernet seem to have DHCP assigned addresses and all of them show 'Connected' status, but we're unable to connect to router either by WiFi or ethernet. After reconnecting cables everything is fine.

I've upgraded it's firmware to latest version but it didn't help.
Current firmware version: 3.0.0.4.380_8375

 

[Lutfij]

Did the issue happen prior to the firmware update? You can try and re-flash the router's firmware after you manually download and update the firmware. You may also want to see if changing the cables changes your experience.

 

[adwil13]

Yeah it started happening before last firmware update, I will try to re-flash it manually and see how it works then.

EDIT:
Right after firmware reinstall and reboot situation happened again. I don't think that something wrong with ethernet cable connected to WAN as WiFi works fine. Also faulty cable could happen on one computer, but odds seem to be very low for 3 cables to go bad at the same time.

EDIT2:
Problem seems to escalate. Yesterday it happened twice, today already 3 times and there's still half of the day to go :/

 

[adwil13]

Alright so the culprit seems to be Realtek 8153 USB card connected to PC with Linux Mint 19. Once it's disconnected everything gets back to normal within 5 seconds...