Loop device remains after core package was refreshed

complete snap novice here trying to understand the basics.
I have noted that each snap install results into a loop device for that snap being created

I have a loop device for an older version of the core snap still lingering around.

1 x core

`:~$ snap list
Name Version Rev Developer Notes
core 16-2.26.9 2381 canonical -``

2 loop devices for core

$ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT ... loop0 7:0 0 79.5M 1 loop /snap/core/2312 loop1 7:1 0 80.5M 1 loop /snap/core/2381 ...

Is there any logic to that (like being able to fall back to that) or is this an error/bug?

/var/snap/core has the older 2312 version yet as well