1. Create a new HTML5 Canvas Platform Project 2. Go into the Publish Settings and Disable Loop Timeline 3. Add 1 additional frame to the Layer_1 by selecting it and pressing F5 4. Create a Square Shape on Layer_1. 5. Convert it to a MovieClip by selecting the shape and pressing F8 6. Leave the defaults and press Enter on the options dialog. 7. Double-click the newly created MovieClip and switch into nested timeline. 8. Inside the nested timeline, create an animation by scrubbing the timeline to frame 10 and pressing F6. 9. Select the Shape and move it 200 pixels up (or whatever) 10. Scrub back to frame 1 and right-click and select Create Shape Tween. You should now have an animation. 11. Navigate back up to the "main" timeline. 12. Ctrl-Enter to Test the project. Verify that you have a MovieClip and by default it is looping. This is the EXPECTED result. 13. Now double click the MovieClip to enter its nested timeline. 14. Ctrl-Enter to Test the project again. The result is that now the MovieClip will NOT loop!
ALSO! If you try to publish from the MAIN timeline, it still WON'T LOOP!!! The file is NOW corrupt!