Edge of screen Particle Too shiny


I made a sequence were the camera panning to the left with some particle in the background.
The issue is that as the camera pan, the particle that enters the screen are suddenly extremely shiny.

The particle system have already a warm up time and I already tried up scaling their Bound Box.

Is there any way to solve this issue without up scaling the render while zooming out the camera and zooming back in after in post - production ?

up, didn’t find any work around atm