Expected behaviour:
A modified wither skull entity would move towards the given direction smoothly, as if it was summoned or naturally created

What actually happens:
Wither skulls with it direction and power modified doesn't display at some points of their trajectory.

Reproduce:
1. Summon a static wither skull:

/summon minecraft:wither_skull ~ ~ ~

{direction:[0.0,0.0,0.0], power:[0.0,0.0,0.0]}

2. Change its direction and power:

/data merge entity @e[type=wither_skull, limit=1, sort=nearest]

{direction:[0.0,0.0,0.1], power:[0.0,0.0,0.1]}

3. See how it starts "teleporting" or "disappearing" (doesn't display most of the time) while moving. However, I think its hitbox doesn't disappear at all.