Issue Not Working: exclude a system package from update in Plesk

[herrMartin]

Server operating system version

CentOS Linux 7.9.2009 (Core)

Plesk version and microupdate number

Plesk Obsidian Version 18.0.44

I had locked the roundcoube for plesk package from updating, as described here

https://support.plesk.com/hc/en-us/articles/360011680259-How-to-exclude-a-system-package-from-update-in-Plesk-for-Linux

but it get's ignored. Every time plesk has a tiny update my plesk gets downgraded to the super old roundcube version included in plesk and I have to update roundcube by myself again.
this is a bit annoying.