Describe the bug

In some cases, the reactive is not working properly.
I have provided a link to the reproduced code for the svelte5 REPL, please check it out.
This problem has been happening since 5.28.2 and does not seem to occur in 5.28.1 or earlier.
This may be similar to #15853.

Reproduction

https://svelte.dev/playground/4b1cfa51635243a193a7f76ad7696b17?version=5.30.1

Steps to reproduce the issue:

1. enter text in inputValue1 of store#0.
2. enter text in inputValue2 of store#0.
3. outputValue of store #0 is changes.
4. Press ADD STORE to add store#1.
5. enter text in inputValue1 of store#1.
6. enter text in inputValue2 of store#1.
7. outputValue of store#1 does not change. Is the reactive broken?

The problem does not seem to occur in 5.28.1.
https://svelte.dev/playground/4b1cfa51635243a193a7f76ad7696b17?version=5.28.1

Logs

System Info

System:
    OS: Linux 5.15 Debian GNU/Linux 12 (bookworm) 12 (bookworm)
    CPU: (12) x64 11th Gen Intel(R) Core(TM) i5-11400 @ 2.60GHz
    Memory: 6.78 GB / 15.42 GB
    Container: Yes
    Shell: 5.2.15 - /bin/bash
  Binaries:
    Node: 22.12.0 - /usr/local/bin/node
    Yarn: 1.22.22 - /usr/local/bin/yarn
    npm: 10.9.0 - /usr/local/bin/npm
    pnpm: 10.10.0 - /usr/local/bin/pnpm
  npmPackages:
    svelte: ^5.28.2 => 5.28.2

Severity

blocking an upgrade