I don't know how to explain it well, but here I go
Sometimes when i drag clips they just go into this mode where it always shows like two clips side by side in the preview and you can only see the same spot of the clip no matter where you are in the clip while it's paused, you can only see what's happening in the clip if you play the video on the video tracks it looks something like this
So I would like to know how to get rid of it and how I caused something like this so I can avoid it the next time
As your "Video Preview window displays a split-screen preview (so you can monitor frames on both sides of the edit point)" in addition to the A/B roll, you probably accidentally pressed 5 on the numeric keyboard (or double-clicked the event edge) and got into Expanded edit mode.
From online Help: "In expanded edit mode, a red bracket is displayed to indicate which event edge will be trimmed, and the track is displayed in an A/B roll."
To exit Expanded edit mode, do one of the following: Choose "Edit" > "Select" > "Exit Expanded Edit Mode" or Press 5 on the numeric keypad or Double-click the event edge or Press Esc on your keyboard. To avoid it, do not press 5 on the numeric keypad (or double-click the event edge)...
Lots of threads on this since it was added in VP 12.