Hi,
I tried re-creating the setup you had:
lxc storage create test dir source=/opt/lxd/test
lxc launch ubuntu:18.04 c1 -s test
ls -la /opt/lxd/test/containers
lxc delete -f c1
And this worked fine, I also tried by creating a new profile that used the “test” pool and that worked fine too.
I’m going to try it with the snap package and see if this is a snap specific issue.