Please run the attached project and repeat the following sequence:
1. Press space to start a new game
2. Immediately and quickly click 10-15 times on "Add more cards" button.
3. If animation stopped after 10th cards, you've reproduced the problem.
4. Press Esc to return to main menu and repeat from step 1.

Once you reproduce the problem you could also press Esc to see that animation actually continues but is not rendering due to dirtyopts. This is gets revealed by FadeOut transition.

I was not able to reproduce this with dirtyopts=false and even with showdirty=true. Without these options this is highly reproducible.