Hi,
PlayMaker has nothing to do with the way Unity deals with system events, if Unity is sending an event, PlayMaker has to forward it. Any other way would create more trouble and frustration than it would solve.
And unfortunatly, I don't think it's not practical nor feasible to double all documentation for these kind of bug/feature,
but I hear you, I am stumbling upon similar issues almost every day, the best approach is to first test a particular feature in a test scene ( Like I did for demonstrating its behaviour), make sure you understand it and then apply it inside your project.
Bye,
Jean