It feels that reporting bugs thought Playmaker interface doesn't work. So I'll duplicate my report here.
Unity 2018.4.31. Playmaker 1.9.4.
This issue bothered me for many years. But I've finally figure out how to reproduce it. Basically, I can't uncheck global status of event if too much objects are using it. In test project specifically it becomes global again after Unity relaunch.
Here's video.
I've sent a link to test project to Alex Chouls PM.