"snap try" broken in lxd containers

I think this is a new breakage of snap try I don’t see documented previously. Steps to reproduce (I’m using an Impish host running lxd snap 4.14 (20450)):

lxc launch ubuntu:focal rbasak-gu
lxc exec rbasak-gu -- systemctl start multi-user.target
lxc exec rbasak-gu -- login -f ubuntu
snap download --edge git-ubuntu
unsquashfs git-ubuntu_*.snap
sudo snap try --classic squashfs-root

This results in:

error: cannot perform the following tasks:
- Mount snap "git-ubuntu" (unset) ([start snap-git\x2dubuntu-x1.mount] failed with exit status 1: Job failed. See "journalctl -xe" for details.

I pastebinned the journal here: https://paste.ubuntu.com/p/yq4Zzn7R39/

I find “This doesn’t look like a squashfs image.” puzzling, if that’s the relevant error. It’s not supposed to be a squashfs image?

The same steps work in KVM (--vm to lxc launch, and lxc shell to get in to it).

I think this is https://bugs.launchpad.net/snapd/+bug/1908424 and was fixed, but requires snapd 2.49 from the deb package.