On the second deer, more than likely, the reason your
friend' s arrow didn' t get a passthrough was because
it struck bone. My setup is very similar to your friend' s,
and it is not going to go through bone. Any chance
the arrow lodged in the offside hip or leg bone? Was
it a quartering shot? Sounds to me like this doe was
on edge, jumping the string like that.

Also, though unusual, I' ve had fatally hit deer run uphill
when it seemed that would be the last place they' d go.
If that doe traveled 250+ yds, pretty good chance
she' s going to survive.

I feel bad for your friend, but also for both deer. It' s
unfortunate that this has happened twice in the same
season. Nice to hear you two did everything you could
to recover each animal.