Just posted a repro about bug in the particle system, case 1027576. We add an particle effect that should follow a target transform, spawn a couple of local particles and let it follow. We pool those particle systems and this has worked fine. Now, when we updated from 2017.1 to 2017.4 LTS, that no longer works correctly. In the repro the particle system renders briefly in an old position, before following the target transform. In our actual project the problem is more severe, the particle doesn't move at all but stays on the initial position, even though systems transform is continously updated to match the target position. I couldn't reproduce that exactly, but I managed to get something that shows clear regression between 2017.1 -> 2017.4. Any ideas, @richardkettlewell ?