I have noticed lately about 1 in 15 arrows bounce off the player for no reason. I have noticed this with skeleton arrows, dispenser arrows, and pillager arrows. I don't play PvP so idk if it happens with player arrows too. I am not taking damage when or slightly before it happens and I am far enough away that the arrow isn't being spawned inside my hitbox.

The consistency of it is very low, but the one thing that seems to influence it is if the player is moving towards the arrow as the arrow comes towards you.