Watchdog Reboot Extreme Networks WS-AP3825i

Hi,
I use several Extreme Networks WS-AP3825i as dumb APs in a Batman mesh. The problem was observed with OpenWrt 23.05.3 r23809-234f1a2efa.
Actually all APs are running quite stable with an uptime up to 3-4 weeks. But occasionally there is a reboot, and I have now managed to log a reboot via the serial console for the first time.
I have already replaced the hardware and the power supply units several times, but the error cannot be localized and happens sporadically on different devices.

The last entry in the log before the restart was as follows:

.....
Sun Mar 31 00:58:09 2024 daemon.info hostapd: phy1-ap1: STA 60:6e:e8:2b:0c:6f WPA: group key handshake completed (RSN)
Sun Mar 31 00:58:09 2024 daemon.info hostapd: phy1-ap1: STA 9c:9c:1f:c8:40:68 WPA: group key handshake completed (RSN)
Sun Mar 31 00:58:09 2024 daemon.info hostapd: phy1-ap1: STA d6:a0:ef:ac:6e:21 WPA: group key handshake completed (RSN)
[436539.485613] PowerPC Book-E Watchdog Exception
[436539.485613] PowerPC Book-E Watchdog Exception

Maybe someone has some info for me what could cause this watchdog exception.

Thanks in advance