Could also be a nock height problem.
I can't say this enough but bare shaft tuning is really the only way to get properly spines arrows.
Every set of arrows I build has one with only maybe 1/2" of fletchng left on it (a modified bare shaft). I use that for tuning the arrows. Once I have them tuned as close as I can, I confirm with broad head tuning. Then later on if I'm having accuracy problems I can always return to the bare shaft to see what's going on ... Arrows too moist, bow lost weight, form closing in, form opening up too much etc. once you know your setup is tuned, the bare shaft is a great training tool.