Heard about Type 99 light machine gun..? In theory, MG shooter could use the bayonet for close combat but in field combat, the bayonet only hindering when firing.
That's a MG by the way. You shooting MG with scope..? Especially in WWII..?
The Japanese used scopes quite extensively on their automatic weapons, more than anyone else. It was useful, and it sill had iron sights so there's no real issue.