Neither my wife or I have had any such issues with 15.4 and I have not seen any online comments suggesting problems.
That said - in early 2025 I had some weirdness I could not resolve without turning off Apple’s AI system. Just after 15.3 came out my wife had a different odd behavior. Since both of us have exactly the same software and our machines have the same chip sets, when either of us have issues it almost has to something specific our individual machine - corrupted files, not being rebooted recently or maybe my face is scaring the video system.
It turns out both our issues were solved by running the Onyx Cleanup Utility with its default settings. You may want to think about a clean up. The tool I used is Onyx which as I understand it is just a front end using the maintenance tools that are part of MacOS that are supposed to run automatically from time to time.