If you open up the Text panel and highlight some text, which creates In-Out points on the timeline, then the Toggle Direct Manipulation button vanishes from the Program monitor if you then move around your timeline and directly select a clip. Clearing the In-Out selection fixes this.
I'm currently doing some soundbite pulls from the text panel so I've been able to recreate this issue several times this morning while working, eventually figured out what was causing it.
Not a huge issue, but it is a bigger problem since you cannot enable or disable Toggle Direct Manipulation with a global shortcut key, you must have the Program monitor in focus to enable to disable. There's another thread on Toggle Direct Manipulation and how it a) doesn't have a global shortcut key like we used to have before you put this icon in the program monitor and b) will pause playback if a clip is selected during playback and Toggle Direct Manipulation is meant to be in active mode.
Currently on 25.1
OSX 13.7.5