It was found that when the user clicks cancel with the user cancel pop up, the dlp agent blocks the paste operation, that data that was blocked is held in a blocked status for the remainder of the session.
DLP Endpoint Agent.
When the DLP agent blocks a paste operation, that data that was blocked is cached in a blocked status for the remainder of the session.
Working as designed.
If this behavior is not desirable you can use the appropriate SDK which does not cache the status.