When a mob is hit by an arrow, depending on the position of the arrow, the HurtTime tag will sometimes be set to 9s instead of 10s (melee)

What I expected to happen was...:
mobs "HurtTime" tag being consistently set to 10s when damaged by an arrow

What actually happened was...:
"HurtTime" is set to 9 when hit at specific angles and speeds

Steps to Reproduce:
1. Make a repeating function or command to test if a mob has nbt of {HurtTime:10s}

ex: execute as @e[nbt=\{HurtTime:10s}] at @s run particle flame ~ ~ ~ 1 1 1 0 100

2. Hit mob with melee attack to prove that melee consistently triggers command

3. Hit mob with arrows at different angles, the command will not trigger seemingly at random when mob is damaged