We do already have mesa 25.1.3-3 in both the Testing and Unstable branches, which — or so I’ve been told — contains the fix, but yes, there have been some problems with mesa for people with AMD GPUs, and generally, that sort of thing does then indeed lead to the package — whichever package it concerns — being held back from entering the Stable branch until the issue has been remedied upstream.
Manjaro is after all a curated rolling-release distribution.
Hint: As a new member, you may want to subscribe to notifications for the Stable Updates category. Every bundled update, whether it’s for Manjaro Testing or Manjaro Stable, always comes accompanied by a dedicated announcement thread.
The first post of the thread contains the changes with regard to the previous bundled update.
The second post of the thread details the potential problems, and how to deal with them.
The announcement thread also always contains a poll (in the first post), and a summary of past issues (in the second post), for those who’ve skipped an update — which is not advised with a rolling-release distribution, but it does happen.