A Sequence clips its children.

A Remotion composition is a tree, and <Sequence from={f} durationInFrames={d}> mounts its children for the frames [f, f+d) — measured from its own start, which is its parent's start plus its own from. So offsets compose additively down the tree, and a child three levels deep starts at a sum nobody works out by hand.

The engine is free and needs no account. A card at frame 15 for 90 frames, and a headline inside it saying from={7} for 120 frames. Both rows are ordinary. The headline actually starts at frame 22 and the card ends at frame 105, so it renders for 83 of the 120 frames it asked for — and the last 37 never happen. Nothing throws, nothing logs, and no warning is printed: what you see is an animation that stops in the middle of its motion. And when the two windows miss each other entirely the child renders for zero frames, which reads as a styling bug for a long time before anybody opens the timeline. Every lane ships a worked example that costs nothing. Writing the report needs credits.