You're right, I noticed the same.
The changelogs are saying nothing about updates in May 2024, especially Synchron Brass, which had an update file of over a GB.
https://www.vsl.info/de/instruments/changelogs/sy-brass
It looks like a bug to me, like Vienna Assistent sometimes forgets the version of the installed products, and therefore displays updates to install. I had to reinstall Synchon Duality Strings recently (it showed as "unistalled"), and I paused the process in the middle because I had to leave. When I restarted the computer, all notifications were gone and the libraries were installed perfectly.