I do not. I have not dug that far into the details of Emby, Kodi, etc.
I can’t recreate that on my system.
Here’s what I tested. Is this the approach you are taking?
I created a managed user “kids” and gave it access to movies with the label “Family.” The user has access to just the one library and has no other restrictions.
I labeled three movies with “Family.”
When I switch to “kids,” I only see the three movies.
When I use my admin user, I see all the movies.
This happens whether I use the local Plex web (to server IP address) or the hosted version (app.plex.tv).
In Settings → Network, I’ve no custom access URLs or networks permitted w/o authorization.
I’m running PMS v1.24.5.5173 on a Synology DS918+. However, that shouldn’t matter. 1.24.0.4930 was released in August. I did not see anything in the release notes for more current versions pertaining to managed users. Nothing in the Plex Web release notes either.