I’ve never actually tried scanning a large library with this MPD version, since I use a separate device running Jellyfin media server that handles around 10,000 tracks, along with the Jellyfin plugin.
I’m not an expert, but the errors look like they are generated by the kernel. The aml_i2c_xfer messages relate to the i2c bus and have nothing to do with the current issue. If I understand correctly, the _hcd_isoc_complete:Uknown urb status -2 messages mean there’s something unusual with fetching / writing data through the USB bus. This is possibly what caused MPD to crash during the scanning stage.
That’s one of the things with using this MPD version on an old distro. The software was compiled with newer libraries, and some of the libraries are meant to work with newer kernels (AFAIK, the Odroid kernel is old… even older than the x86 version that Volumio uses). So it is possible that during the scanning stage, a library fetches data from the USB bus with the old kernel that happens to have a memory leak bug, and that eventually leads to MPD crashing.