It might be just in my head but I also feel like stone arrows miss as described by the OP more often than iron arrows do and that the "glitch" happens even less often with the better bows/ crossbows which lends some credence that there is an intended "hit roll" probability at play even if your aim is visually spot on. I do agree that having a visual result where the arrow appears to pass through the zombie is a poor feedback loop for the player IF things are behaving normally and it isn't a glitch.
Also, I notice (and it can't just be in my head) that the "bug" doesn't seem to happen ever for me when I am shooting a stationary sleeper. Those arrows always hit perfectly for me. Could that again be the game giving me a 100% "to hit" vs a non-moving target? Could that be proof that the actual issue is as zztong stated?
@Jugginator any idea? Is there a ticket for this commonly mentioned player feedback?
Or can we keep messing with Meilo?