Thank you for sending the screencap video - it explains everything and I now fully understand the issue that you’ve encountered. I’ll share this with our engineering team so that they can see the problem for themselves.
Have you tried to render the result to see if this helps the playback issue that you’re seeing in the Premiere timeline? I find that doing so results in full speed playback with no dropped frames. Obviously this won’t help when you’re in the Particle Illusion custom UI though.
So what can we do in the short term to make working with Particle Illusion a smoother process for you? Well looking at how you need to use Particle Illusion, I can tell that you might want to try using a workflow whereby you either render the effect layer and then continue to work with it or render and then export the particle effects from Premiere as a clip, then import the rendered clip and layer this over your animated still image - following this method should give you real-time playback in the Premiere Pro timeline. The workflow I am suggesting here would be :
(1) in the premiere pro timeline, add a new track (V2) above the animated still image that you want to have as the source (V1), and add a transparent video element to the V2 track making it the same length as the animated image source
(2) apply Particle Illusion to the media element on the V2 track and select the burning embers preset
(3) turn off the visibility of the V1, the track containing the animated image source
(4) all you should be seeing now are the particles - render this and export the result to disc
(5) import the rendered / exported particles result, replacing the media element on V2 with the imported particles clip
(6) turn on the visibility of the V1 track
(7) in he effects control panel, under the Opacity group twirl down, set the apply / blending mode to generate the result / look that you had in mind for this shot, maybe try the Screen mode.
I know it’s kind of clunky but the problem is that you’re using Particle Illusion on a 30 second clip - that’s a really long clip in the world of Particle Illusion but we recognise this as something that you and others need to do - hopefully we will soon be able to offer an update to the software that will eliminate the long delay and staggered results that you’re seeing while using Particle Illusion as a live filter on long clips.
I hope this helps.