Ar71xx and ATH79 crash on wireless settings change ( ath9k )

I've got some strange behavior on both ar71xx and ATH79 targets with the current master build on ar71xx and ATH79 targets ( porting from generic ar71xx to generic ATH79 ).

Every 3rd or 4th time when I call/etc/init.d/network reload after changing txpower or channel the system hangs right after the wireless interface comes back up, sometimes the system hangs, other times i get a kernel dump.

at first I thought my VLAN configuration and batman-adv could be contributing but I've removed those from the build and it still happens.

any suggestions on how I can find out why the crash is happening or any open bug reports that match this ?
uboot :

    SOC: AR9330 rev. 1
    CPU: MIPS 24Kc
    RAM: 64 MB DDR2 16-bit CL3-4-4-10
  FLASH: 16 MB Winbond W25Q128
    MAC: 70:B3:D5:71:50:00
 CLOCKS: CPU/RAM/AHB/SPI/REF
         400/400/200/ 25/ 25 MHz

uname -a :Linux OpenWrt 4.14.101 #0 Mon Feb 25 14:49:16 2019 mips GNU/Linux

the most recent crash dump at this gist ,

dmesg output here

I use the following script to change channels easily: call it by " change 1"

#!/bin/sh

LOWEST=1                # cannot set to channels lower than this
HIGHEST=13              # highest channel 

# check that we got an input
if [ $# -lt 1 ]
then
  echo "Usage: $0 [channel no ($LOWEST .. $HIGHEST]"
  exit 1
fi

if [ $1 -lt $LOWEST ];then
                >&2 echo "$1 is not a valid channel ($LOWEST .. $HIGHEST)"
elif [ $1 -gt $HIGHEST ];then
                >&2 echo "$1 is not a valid channel ($LOWEST .. $HIGHEST)"
else :

uci set wireless.radio0.channel=$1
uci commit
/etc/init.d/network reload
fi

did a bug report as well in case its more appropriate : https://bugs.openwrt.org/index.php?do=details&task_id=2149