I kind of had the same issue awhile back, especially under 10 yds. Could see the arrow fishtailing somewhat. Would hit where I aim, but often nock was right or left. After paper tuning and bare shaft, I concluded that my arrow was still going thru the "paradox" for almost 10 yds before it straightened out. I shoot a longgbow, that isa not centercut, so after researching alittle, this a what seems to be causing such fishtailing in my opinion. Taz