Describe the bug

If a <svelte:component> tag is used inside of a element with a svelte transition (like in the code below) and the this prop is changed while the transition is playing then the old component will stay mounted alongside the new one.

{#if open}
  <div transition:fade>
    {#if component}
      <svelte:component this={component} />
    {/if}
  </div>
{/if}

Edit: This behavior also seems to occur if a there is a transition inside the component that is provided to the this prop.

Reproduction

https://svelte.dev/repl/c3000501dc154b88b93cf37c58b350b7?version=3.43.0

To reproduce click the Open button followed by clicking the Confirm buttons.

Only one component should be visible at a time but all components stay mounted.

Remove transition:fade in Container.svelte to get the proper behavior.

Logs

No response

System Info

Linux 5.13.13-arch1-1, Brave Version 1.26.74 Chromium: 91.0.4472.124 (Official Build) (64-bit)

Severity

annoyance