I was recently trying to optimize my shell startup time, and I noticed that
zsh --version said that it was x86-64, while
bash --version reported (correctly) that bash was running on aarch64.
file $(which zsh) and
file $(which bash) reported, also correctly, that the binaries themselves were universal, i.e. they were fat binaries that could run on both architectures.
I’m not sure why this happens, but others seem to be having this issue too.