I downloaded the 64bit ISO from here: http://download.linuxaudio.org/avlinux/AVL-MXE/64bit/
When I read out the sha256 sum I get 618778f9eec446f366a54f2af19283fd0fc67efb667cb42d48674ff2ac05109f AVL-MXE-2020.12.03-xfce4-amd64.iso
I repeated the download and get the same sum.
This seems to be different to your sum:
1450cc402571fd598f909ac55cd7957676bd31ae27f3beec3f16d16dbb838e1af951a8c206cee9deb94a0e9c7effee96cd04ed9b9469d26266fc1868fe988bae AVL-MXE-2020.12.03-xfce4-amd64.iso
Is there something wrong / confused?
What's the best when copying the image to a penstick? Should I use dd?
Another question: I'm used to (more or less