[GAMEPLAY]game stucks after a spectations has ended

whenever i spectate when the game finishes and a nexus is destroyed the game just stays and the victory banner does not show. when this happens all the sounds will go except the sounds from champs like when karthus casts his wall and say "your bodies will betray you". you can go back and forth in all the game but you cannot pause anymore and the only way t come out is to press alt+f4.