I got mine from Ty and it sometimes has red in the pstem from time to time (comes and goes) and has light colored winestain/spotting like yours when young. My pstem has never shown as much red as yours but that could be due to ph, too much/too little of some nutrient, amount of sun, etc. Mine does show some red pinstriping along the edge of the leaf but its not as prevalent as yours.
I've been documenting my quest for patupi fruit on this thread with lots of photos:
Patupi!!!