Border around characters excluding special characters

The problem appears when I copy a piece of code from one window to another, and since then the characters from a-z always have a border around them when I try to move the cursor somewhere else it always returns to the end of the text with a border around it, the only way to get rid of this border is to press the space key or a special character.
When I cut and paste it can paste multiple times like copy and paste
The most annoying thing is that now it can't suggest code with a few hint characters and I have to completely press each character manually.

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