I just installed U5 and all my particle systems which have ‘Prewarm’ checked are bugged. The prewarmed particles mess up the ‘Shape’ property completely. All particles which are being emitted after those ‘initial’ ones are working perfectly fine.
To better understand what i mean, take a look at this screenshot (the large blue lines are my particles, the little blue frame is my Shape, the particles should be emitted all across the Shape, but they are not. They are not centered either, which is strange (this means the Shape module is not completely ignored, because turning off the Shape module centers them to local 0,0,0).):
If anyone has a solution for this, please tell me, you would make my day!