Yesterday (3/12/26) I had a Windows update and it appears to have fixed my issues with selecting items in the Start menu. It is no longer opening random apps/programs when I make a selection. I have restarted my computer multiple times and menu selections continue to function properly for me.
I am having the same issues -- I have Start set up to view as a list, but sometimes when I make a selection the menu turns into the keyboard pattern (letters/numbers), or it will open a different random app or folder. It's incredibly annoying, especially if the newly opened app decides it wants...