TP-Link Archer C6U mt7615 interrupts problem

I can confirm the ksoftirqd/3 cpu load behavior. I have 3 of the same routers on the stable release, strangely enough, I don't see it on the other 2. Both are online much longer than the 3rd one.

root@caretaker3:~# uptime
 13:09:25 up  1:38,  load average: 1.61, 1.65, 1.67

root@caretaker2:~# uptime
 15:55:55 up 14:58,  load average: 0.00, 0.00, 0.00

root@caretaker1:~# uptime
 13:09:52 up 14:58,  load average: 0.06, 0.03, 0.00

All are running:

OpenWrt 21.02.1, r16325-88151b8303

caretaker1 -> main router (WDS master)
caretaker2 -> WDS client
caretaker3 -> recently installed, WIFI cards are disabled , just connected on caretaker2 with LAN cable

Only caretaker1 is connected using WAN interface here.

root@caretaker3:~# cat /proc/interrupts 
           CPU0       CPU1       CPU2       CPU3       
  8:    1583542    1583518    1583430    1583485  MIPS GIC Local   1  timer
  9:     384848          0          0          0  MIPS GIC  63  IPI call
 10:          0      21999          0          0  MIPS GIC  64  IPI call
 11:          0          0     684494          0  MIPS GIC  65  IPI call
 12:          0          0          0      17403  MIPS GIC  66  IPI call
 13:  153206524          0          0          0  MIPS GIC  67  IPI resched
 14:          0  160359768          0          0  MIPS GIC  68  IPI resched
 15:          0          0    5045583          0  MIPS GIC  69  IPI resched
 16:          0          0          0      32542  MIPS GIC  70  IPI resched
 17:          0          0          0          0  MIPS GIC  19  1e000600.gpio-bank0, 1e000600.gpio-bank1, 1e000600.gpio-bank2
 19:         12          0          0          0  MIPS GIC  33  ttyS0
 20:          0          0          0          0  MIPS GIC  29  xhci-hcd:usb1
 21:      18710          0          0          0  MIPS GIC  10  1e100000.ethernet
 23:         23          0          0          0  MIPS GIC  11  mt7603e
 24:         16          0          0  327156842  MIPS GIC  31  mt7615e
 26:          0          0          0          0  1e000600.gpio   8  keys
 27:          0          0          0          0  1e000600.gpio  10  keys
ERR:       5371

I re-checked and both radio's are disabled on this router.

The router that is doing the most the ERR counter is not rising:

root@caretaker1:~# cat /proc/interrupts 
           CPU0       CPU1       CPU2       CPU3       
  8:   13611287   13611013   13610515   13611387  MIPS GIC Local   1  timer
  9:     982356          0          0          0  MIPS GIC  63  IPI call
 10:          0      43540          0          0  MIPS GIC  64  IPI call
 11:          0          0     854987          0  MIPS GIC  65  IPI call
 12:          0          0          0      78003  MIPS GIC  66  IPI call
 13:    1152587          0          0          0  MIPS GIC  67  IPI resched
 14:          0    1176937          0          0  MIPS GIC  68  IPI resched
 15:          0          0     933843          0  MIPS GIC  69  IPI resched
 16:          0          0          0     579682  MIPS GIC  70  IPI resched
 17:          0          0          0          0  MIPS GIC  19  1e000600.gpio-bank0, 1e000600.gpio-bank1, 1e000600.gpio-bank2
 19:         12          0          0          0  MIPS GIC  33  ttyS0
 20:          0          0          0          0  MIPS GIC  29  xhci-hcd:usb1
 21:     180854          0          0          0  MIPS GIC  10  1e100000.ethernet
 23:         22          0          0          0  MIPS GIC  11  mt7603e
 24:         18          0          0    1731029  MIPS GIC  31  mt7615e
 26:          0          0          0          0  1e000600.gpio   8  keys
 27:          0          0          0          0  1e000600.gpio  10  keys
ERR:         72