Unfortunately this is nothing we can do much about, if another application already reacts to the hotkey...
Here is more information:
Actually "Won't fix" is not 100% correct, the next Greenshot will probably use a different way to react to the printscreen key. But it might be possible that other applications still respond to this, which is nothing we can prevent.
this is OneDrive behaviour: there is an option that alows you to save all screenshots to OneDrive automatically. You will solve this issue by disabling this option in OneDrive settings as it's another processor for PrntScrn button press event and OneDrive has higher riority for that.