Adding /usr/lib/x86_64-linux-gnu/mutter to /etc/ld.so.conf.d/x86_64-linux-gnu.conf and running ldconfig fixed it for me. ldconfig doesn't process directories recursively and the mutter directory was missing.
Here's what the conf looked like before the edit. # Multiarch support /lib/x86_64-linux-gnu /usr/lib/x86_64-linux-gnu
