Surprised no one reported this before. I just noticed today that he didn;t give me a new grenade after tossing one. I think this has been broken for so long everyone forgot about this feature.
Anyway... I found out how to fix it, it got broken by a steam update which changed an event. I found a more reliable way to check for a grenade toss anyway. I will post some code examples later so any other heroes that check for gren toss could be fixed (fartman for example)