Describe the bug

I have an app with some deep state where I'm mutating the deep state with a delete operator. I understand this should all be reactive due to the delete method trap on Proxy, but I'm not seeing my derived state update right away, I have to call delete a second time to see the UI update. See minimal repro example attached. You have to click the Delete button twice to see anything happen.

Reproduction

https://svelte.dev/playground/cfdfaac67da34188ad9bd2fbfe148885?version=5.27.2

Logs

System Info

bunx envinfo --system --npmPackages svelte,rollup,webpack --binaries --browsers

  System:
    OS: macOS 15.4
    CPU: (8) arm64 Apple M2
    Memory: 99.22 MB / 8.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.12.0 - /usr/local/bin/node
    npm: 10.9.0 - /usr/local/bin/npm
    bun: 1.2.7 - ~/.bun/bin/bun
  Browsers:
    Chrome: 135.0.7049.85
    Safari: 18.4
  npmPackages:
    svelte: ^5.0.0 => 5.23.1

Severity

blocking an upgrade