so what I’ve found out in my own render is when the temporal AA sub sampling is cranked up it will take time to load the subsamples but the particle system will keep running thus ending before it should, I added the systems life cycle track to the sequencer and it seems to have fixed that issue.
The only draw back is the particle system won’t have any AA.
this tutorial helped me set it up Niagara 4.25: Scrub/Control Niagara System via Sequencer - YouTube