Ah ha! What you have found my friend is called false neutral. It usually means that gears and engaging levers are spinning with sub-millimeter clearance between them. Usually it mechanical reasons, from worn gears to a bent shift fork to poorly adjusted shift linkage to just rider error (not a positive enough shift) Sometimes while you're in it, it'll sound like loose nuts and bolts chattering inside the transmission. Pretty common in cassette type close ratio transmissions.Hello,
Do you guys have notice a neutral between 5 and 6 gear?