Hi @TonyB.ca, I have another NanoPi Neo3 and I'm experiencing the same you are, I wonder what could be happening.
Right now, I have a stable build on Jammy, but I have another microSD with which I'm making tests to try to see how come the actual MAC from the device isn't picked up. Just now I finished building a current Bookworm based Armbian, but with u-boot being that of 2023.04 instead, same outcome. I know the board was released with u-boot 2017.sth, but I thought, what the hell, perhaps it's a bug in the 2022 versions.
In any case, I'm at a loss, I'll try to find other boards that ship with real MACs and see if there's any difference on how they're defined in configuration files or kernel builds. For example, the NanoPi R4S used to ship with a unique MAC, but due to shortage of parts or something they can't guarantee that now unless you place a considerable order; that doesn't happen with the Neo3, even if ordered just one they do come with a unique address.
If anyone comes across this thread and knows at least where we should look into, we'd appreciate it! I'm new to this kind of low level stuff.