Some particles lose initial speed when they were created.

For example the vanilla campfire smoke particle, when summon a smoke particle, the initial speed is 0, which is different from the same particle in 1.20.70 Release, which causes its floating height become lower than before as you can see in attachment screenshots.

In addition, the fire smoke particles won't move upward.

However the particle JSON file have not been modified, which means there should be a problem with the way the game runs particles, i don't know the condition, but it also affects some of my rewritten particle.