WDS 2xWDR3600 random connection drop

Hello, i have 2 WDR3600 (v1.2 and v1.4) bot with LEDE Reboot 17.01.4 r3560-79f57e422d

The first (gateway, dhcp server etc) is configured (from LuCI) as
WDS AP SSID 2.4GHz (40Mhz Ch auto) + 2 More SSID For clients + 1 5GHz SSID

The second one (basically a repeater, fixed IP DHCP off):
WDS Client (that is the only one that connect to the WDS AP SSID) on 2.4GHz (40Mhz Ch auto) + 1 SSID for clients + 1 5GHz SSID

The issue is that the link btw the 2 routers will drop randomly and came back after like 30secs during the day and i'm not able to find the cause (that looking at the log seems to be br-lan: port 4(wlan0) entered disabled state of the second router).

Here the Kernel logs of the 2 routers with like 6h of uptime rebooted at same time, looking at the second one log there where 2 drops

first: https://pastebin.com/raw/men9ybCd
second: https://pastebin.com/raw/YWLZmhqq

Someone know a possibile solution? is an hardware fault? is a LEDE fault?

PS. The link btw the 2 router is good and i exclude the distance as problem
The first router of 2.4GHz radio is set to Tx-Power: 21 dBm and is the max
The second router was set 21, i've gone to 20 and seems the drops started to be a little less, now i'm tring with 19dBm, but this can be just a coincidence

See these forum threads on WDS drops...


already gone in to the wild... probably i need to assume the last comment of this task as the definitive answer: