Since it makes very little sense to check more than once after opening the app - other apps don't randomly put data into the clipboard in the background (I guess they could snag something from a Mac over Handoff but that already pops up an invasive system progress bar giving away the game) - I'm going for incompetence over malice.
Maybe not even incompetence. It could just be that some sort of periodic UI refresh triggered the clipboard lookup, because why bother caching clipboard data if you can just read it on the fly when updating your UI?
