i finally need an answer but since i wont get one i will list some stuff and then you vote pls. (or you just skip reading and vote)
old garens e was spamable and the damage stacked. some people think it was a bug, many seem to think it wasnt.
theres champs like rumble and corki who could also spam their e in urf but the damage didnt stack.
since garens e "rework" the bug is gone. kinda like how teemos q bugged out graves autoattacks, since they fixed this teemo can no longer blind gromp.