Whenever there is a clip before "black" on the timeline, and the playhead is going over that clip..at the very end of that clip, the program monitor has this weird line going vertically down the screen and about half the program monitor goes black. It does this with every project too. Also, inside the program monitor, the time ruler automatically zooms in every single time I overwrite or insert a clip into the timeline. Why is this happening all of a sudden?
The line you describe is part of the new end-of-sequence indicator, which consists of a vertical black band about one-fifth the width of the frame, bordered on the left by a white line.
I have not encountered the zooming behavior you describe.