what causes it?

[Dub]

ok. everythin was goin REALLY smooth. here. but ummm WHAT THE HECK IS THAT?!?!?!?! jeez. ok i guess its seom lag spike.. but what may have caused it? that way i can prob try to eliminate it and it wotn mess up my almost perfect chart x[



also. why does the quality say only good? ive seen others that reach almost perfect rating. whats the difference?