I can't figure out what puts it in this mode. It is like the index pointer to the mode drop down box gets corrupted from when they added the two extra modes(3-4 Point & Replace) to the bottom. When acting up and Overwrite is acting like Insert or Smart select, if you select smart Editing mode, it works like Overwrite mode.
I'm doing something to get it out of sync, but I don't know what or when. All of a sudden it does it and I've touched 40-50 clips, so I can't point to it. I place all my clips on my project with Insert mode. I then switch to overwrite mode when I'm adjusting, replacing, and editing clips. To insert or replace a clip on the timeline with a longer clip, I Shift-Ctrl Click the clips to the right of where I want to make a change, move everything to the right, insert, replace, or make my changes to the hanging left-hand clip, then Shift-Ctrl everything to the right and pull it back with the Magnetic Snapping on to prevent clip fragments. Doing thi allows me to keep all tracks to the right of my edit in sync.
It does this in PS23 & PS24. It never did it before. I purchased, but never installed PS22, so I can't tell you if it does it. If I restart PS23 or PS24 it starts working properly again.
What version did they add 3-4 Point & Replace modes to the bottom of the drop down list? That is when it started.