In this scene both the fire trail as well as the resulting explosion and debris are all particle systems and have Sort set to None. This often creates jarring artifacts. The situation doesn’t happen when sorting is set to something other than None but for obvious reasons it’s not preferred to incur that performance penalty since I can live with it being unsorted.
Here’s the version with Sort set to Camera Distance. As you can see there’s an oddity here of the trail size being different even though the only thing that’s changed is the Sort.
The sorting method affects whether the particle system is GPU or CPU driven. The GPU version has a few bugs that we are aware of so if it’s not a huge deal you could try using the CPU version which should work OK.
Yeah, I know. I simply wanted to not pay the penalty here and wasn’t aware that you guys are already on it.