You can read more about it
here: Cubase automatically replaces some plug-ins used in old projects? - #6 by steve
and here: https://support.native-instruments.com/hc/en-us/articles/12972701353757-Notes-about-Auto-Migration-of-Kontakt-Versions-in-DAW-Projects
Since this used to work well in an older Cubase version with exactly the same plugins, I assume the problem is not on NI`s side.