I first noticed this on InDesign and went to Adobe's forums. Everyone ripping Adobe. So I tried Apple preview and the 'untitled' text is highlighted s you can type in the name of the file your saving. I thought I'd try this with APublisher and same thing. No highlight. So it's not just an adobe problem. However I did notice the highlight flashed for a split second with Publisher. I'm on Monterey 12.01 and 1.10.4.
However the highlight problem with InDesign was also there with Big Sur. Not sure about Publisher.