Hiccups occur when an object that has lodgroup first appear in frame, the object is rather low on polygon at <1000
I use LOD group mostly to switch shaders, from hi fi to lo fi.
The hiccups happen in game and when navigating in the scene view.
Is the use of LODgroup not recommended or has new restrictions?
Warming up your shader in advance would help.
How do I do that? Heating blanket or bouillote? If so, you have a specific model in mind?
Brilliant - still etting hiccups but this time, it’s shuriken on first time display… any ParticleSystem.Warmup?
What version? We have improved this in the latest 5.4 betas.
Also, you may want to consider turning off prewarm on any particle systems that don’t require it.
b21
What determines “don’t require it”?
Just whatever that means for your game… I guess it depends on your content and use-cases 
Another idea: to prewarm them from script, try ParticleSystem.Simulate with a 0 time step.