key block causes ghost elements

[hgl]

Describe the bug

See reproduction.

Reproduction

1. Go to the playground
2. Click the add button quickly
3. See multiple "Hello world!" appear, some instantly show and hide.

Logs

System Info

System:
    OS: macOS 15.3.1
    CPU: (12) arm64 Apple M2 Pro
    Memory: 57.64 MB / 32.00 GB
    Shell: 4.0.0 - /run/current-system/sw/bin/fish
  Binaries:
    Node: 18.20.7 - /etc/profiles/per-user/hgl/bin/node
    npm: 10.8.2 - /etc/profiles/per-user/hgl/bin/npm
    pnpm: 10.6.1 - /etc/profiles/per-user/hgl/bin/pnpm
  Browsers:
    Chrome: 134.0.6998.89
    Safari: 18.3
    Safari Technology Preview: 18.4
  npmPackages:
    svelte: 5.23.0 => 5.23.0

Severity

annoyance

[hgl]

This is actually correct behavior.