Specific projectiles are rendered incorrectly when thrown(snowball, splash potions), with their initial motion modified by a datapack.

Snowball, for example, its trajectory is rendered incorrectly according to its modified motion for the first few ticks of its movement, then a sudden switch to what its supposed to be. Same issue happens to splash potions.

I've check the motion data of it, the motion is modified at the 2nd tick after it is thrown, but theres a sharp change in trajectory ticks after.

Freezing the game with carpet mod before throwing the snowball and then unfreezing it gets me the correct trajectory, and the datapack works totally fine with other projectiles like arrow and trident, thus I assume its a rendering issue.

The datapack is attached below, I only kept the relevent part of the pack.