I am having this strange issue in my HomeHub 5A for quite some time. First I thought it may be becasue of power surge or something. But now sometimes even a power off/power on from Hub power switch also triggers this behavior.
I was only able to capture the Log from my USB because 2.4GHz WiFi is not accessible anymore in this situation. I do not use 5GHz because it takes more RAM and I only own one device, my phone, which can use 5GHz.
Anyway, the situation is that sometimes, a power off/power on cycle triggers DMA errors on 2.4 GHz WiFi and it no longer boots up unless it gets restarted somehow which is only possible either through serial access or through 5GHz WiFi (which I do not use anymore) or the physical reboot button which I think is no longer working in v19.07.0.
One more thing is that I am seeing this behavior from v18.06 because I started using this Hub with v18.06 from the start and the Log that I got from the USB is: https://pastebin.com/UN0xVd60
Is this related to any bugs or could there be a race condition that triggers this behavior?
WAN MAC address changing on reboot is a known bug. See section 7.6 of manual about 'wan_dev' and MAC address Override options to set it.
(if you factory reset the hub and use the grey DSL port, the mac address is correctly defined in wan_dev section of /etc/config/network when inspected)