Jellyfin cloning

[TheDreadPirate]

As long as your are copying /config and /cache in their entirety, and that BOTH A and B STOPPED when you sync the two instances, it should migrate no problem.  As long as the media is in the same location from the container's context.  Also, clear your browser cache when you access B to ensure you aren't viewing a cached instance.

Circling back to your opening post.  Avoid ISOs.