Particle Disapear

Paricles dissapear for some reason. i gave them 9999 lifetime ( and they still alive according to this counter) i used Find and saw it is still exsist and animating and there are 19 particles.

even tried to play with the renderer and put it on vertical billboard and added sort mode by distance. ( nothing should block the way because they are in blue space but still did it )

help me plz. i am clueless

Edit1:

the functions that i use on the particles : GetParticles SetParticles

and the changes that i make on the particles themselves are: change velocity change color

i cant see any difference between before and after the disappear ( except the obvious that i can't see them)