RT-AC58U 5GHz issues

[Mic Tie]

Several times per day my AC-58U refuses to work on the 5GHz band.
Looking at the system log I can see the following repeating 50-100 times:
Jul 14 12:59:02 kernel: Switching to Tx Mode-1 Threshold 0
Jul 14 12:59:10 kernel: Switching to Tx Mode-1 Threshold 280
Jul 14 12:59:14 kernel: Switching to Tx Mode-1 Threshold 0
Jul 14 12:59:19 kernel: Switching to Tx Mode-1 Threshold 280
Jul 14 12:59:28 kernel: Switching to Tx Mode-1 Threshold 0
Jul 14 12:59:34 kernel: Switching to Tx Mode-1 Threshold 280
Jul 14 12:59:47 kernel: Switching to Tx Mode-1 Threshold 0
Jul 14 12:59:49 kernel: Switching to Tx Mode-1 Threshold 280
Jul 14 12:59:56 kernel: Switching to Tx Mode-1 Threshold 0
Jul 14 13:00:01 kernel: Switching to Tx Mode-1 Threshold 280
Jul 14 13:00:04 kernel: Switching to Tx Mode-1 Threshold 0
Jul 14 13:00:07 kernel: Switching to Tx Mode-1 Threshold 280
Jul 14 13:00:13 kernel: Switching to Tx Mode-1 Threshold 0
Jul 14 13:00:16 kernel: Switching to Tx Mode-1 Threshold 280
Jul 14 13:00:25 kernel: Switching to Tx Mode-1 Threshold 0
Jul 14 13:00:25 kernel: Switching to Tx Mode-1 Threshold 280
Jul 14 13:00:27 kernel: Switching to Tx Mode-1 Threshold 0
Jul 14 13:00:31 kernel: Switching to Tx Mode-1 Threshold 280
.....

When this is happening, 2.4GHz is working fine, 5GHz disconnects.
After 1-2 minutes the router start working normally, until the whole repeats a couple of minutes or hours later.

Asus exchanged my router 2 moths ago, the issue was gone, but now also the new router shows the same problem, and it's getting worse - longer and more often.
I could use 2,4GHz, but then the speed would drop from app 350Mbps to 60Mbps

Any idea what could cause this, and/or how to resolve?

 

[puc2000]

I have the same issue on a GL.Inet B1300 ..... any new ideas ???

 

[Mic Tie]

It might be some overload problem.
After moving some of the 5GHz connections to 2.4GHz the situation has somehow improved, but it comes at the high price of significantly lower speed.

 

[corbinian1]

Mic Tie same issue here. Apparently it was an issue with the chipset since it was the first time they implemented the MU-MIMO and Beamforming. I’m seriously thinking of replacing it with an AC86u.