Comment 2 for bug 1861026

python3-magic uses ctypes.util.find_library('magic') , which actually uses `ldconfig -p` to find installed libraries. That's not honoring the LD_LIBRARY_PATH and it is getting your host-installed library list. With the "fake" hit of your host's /usr/lib/<arch-triplet>/libmagic.so.1 (which gets distilled down to "libmagic.so.1"), it ends up loading the library fine afterwards.

Related: https://forum.snapcraft.io/t/issue-when-snap-uses-pythons-ctype-util-find-library/9690

So, in short:
(1) ctypes.util.find_library() is currently broken for snaps.
(2) I don't know that it's an issue, but I wonder if the host ldconfig cache shouldn't be leaking for strict snaps? In this case, it's clearly triggering system-specific behavior changes...

If `ldconfig` were to provide the correct library list in a snap, it would presumably address this without having to patch ctypes. Something like what is discussed at: https://forum.snapcraft.io/t/effects-of-dynamic-library-caching-on-snap-startup-performance/14454