Sorry, I did not notice that you were using the delay option, doh.
It sounds like it should be working the way you have described it. In my noob experience I had simmilar issues, where I copied and pasted something and then forgot to change the variable (so I would have two FSMs saving different GOs to one global variable) and stuff, not saying you necessarily did this , but just brainstorming.
But in regards to the debug I think what Alex refers to is being able to view variables in inspector during play. This would help know if it really is the GO you expect in the variable.
Basically select the game object that contains the FSM, in the variables tab, on the editor, select the 'bubble container' global variable and tick the 'inspector' box.
Then when you play, click on the object and view the FSM in the GO's inspector, it will show you the name of the actual GO contained by the variable. If this is not the same as the actual object you are trying to send an event to, then something is wrong.
(I've never done this with Global variables, but I think it should Work the same).
On a side note; if the prefab is the only game object using this global event, as a test and, at least a temporary, workaround try to send the event by 'broadcast to all'.
Good luck with it.
Screenshot:
(This is a screenshot from Google imagez , in the image 'network sync' is highlighted, but you need the 'inspector' tick box just above it)
https://www.google.co.uk/search?q=show+in+inspector+global+variable&client=tablet-android-asus-nexus&rlz=1Y3NDUG_enGB514GB514&espv=1&prmd=vin&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjrvbXljZnNAhUHIMAKHdRVAkQQ_AUICCgC&biw=962&bih=553#tbm=isch&q=playmaker variables show in inspector global variable playmaker debug options&imgrc=tvy2rxLzJGY3xM%3A