Why do animate:flip directives not allow siblings in an each block?

[TravisBoatman]

I'm having a hard time understanding the technical reason behind this.
For example:

{#each nodes as node (node.Id)}
	<div class="node" animate:flip={{ duration: 300 }}>
		
	</div>
	<div class="sibling">

	</div>
{/each}

Will give you the compiler error: An element that uses the animate: directive must be the only child of a keyed {#each ...} block https://svelte.dev/e/animation_invalid_placementsvelte(animation_invalid_placement)