Congrats on the new bow, I' ve heard those machete' a are nice!!
As far as the corscrewing, as long as your not torquing the grip upon release- I doubt it' s your bad form. Most likely the rest needs some adjusting for centershot, or your getting fletching contact. And fletching look abused?

If your shooting a string loop you don' t need that rubber tube. You can use the loop to center your peep. Once you get the string broke in you might have to adjust the loop a tad to one side or the other, but it will work and help pick up some speed and reduce noise at the same time.
Good luck with it.