@fermmmm Hi! I tried to replicate your code with my debug setup, where I can lower the FPS on command. I ran it at 2 FPS and OnComplete was called correctly. Instead, I found a bug where speed-based tweens weren't evalued correctly at startup (at low FPS). The update I'm attaching fixes this. Can you check if it fixes also your OnComplete issue? @Devil_Inside The reason is what you said, but I never realized it could be a problem. Mhmm, maybe I could add safe-mode to callbacks too, and cancel them if they throw an error? What you think?