Some more information that I have come across.
It appears that this behavior is also observable without verse.
If one hooks up an input_trigger_device “On Input Pressed” Event to a Switch’s “Toggle State” Function and sets it up with for example Swap Quickbar Creative Input or Crouch Creative Input it will turn the switch on and then very quickly turn it off again, indicating multiple firings.
However! This whole problem does not appear to be the case for the Harvesting Tool Creative Input, which only fires the function once and properly switches the Switch’s state once per input.
Hope this helps tracking down the issue.