External interrupts to MCU from ADV7511
It's not clear what this "ADV7511" is or how it's even relevant.  In any case, mechanical connections bounce.  This happens both on make and on break.

If the bouncing matters to you application, then debounce the signal.  That really should be obvious.

How long you debounce for depends on how long the connection bounces for, and how long it is acceptable to wait before reacting to the new condition.  It seems the action you want to detect is a monitor being plugged and unplugged to/from a computer.  It seems like a few seconds delay would be acceptable, but that's really something you have to decide.