Reduce motion is on · previews stay still
Time drift
Come back from a background tab and the animation jumps; every recording comes out different.
Cards that use this check
0 cards, 0 with it as the free first checkAbout this collection
Why it happens
Animation runs on Date.now() or an accumulated delta, with no fixed step and no seed.
Check / fix block
FreeCheck: animate only from a frame count or clock.getElapsedTime() with a capped delta; seed all randomness. Two 5-second recordings match frame by frame.
The library itself is public. On a card, the first check is free; the rest and the contact sheet are Pro.