Bug: Re-rendering only happens once

[alex-way]

Describe the bug

When performing a chain of derived statements the first re-render works correctly but any subsequent expected re-renders don't happen.

I'm not quite sure what's the cause of this currently, but this was working perfectly fine in svelte 5.43.3:

https://svelte.dev/playground/52b72be7ad104bfa91fe6fcaf475a63d?version=5.43.3#H4sIAAAAAAAAE22QPW-DMBCG_4p7ymAki6RfCw2R2k6ZM8YZiH20VuFA9pE0Qvz3yiSFDh393nPPWW8PVNQIGbx1H6CgdBUGyPY98KWNcQxA_UKvbZuGE1Ycs2MR8L_cNMRIHCCDdTDetbzRpNnVbeNZ9LuR2yEPovRNLTRcN5ceC8Pu5Pii4SVumIYCC2eDyMV-pe7Vg3pUT-r58GcaEGk7EoRnMbllEpmJ6mjmFha9O6GVzoa0dBWjl9LZROQbcXfD0s8ixCwZNTyLTOc9Em_tX9FkTwuWq9vOwlFo0fA8TTStl3MhtD52zA2J2HSu4frSIBoylTNfeS_HP01ua-V0PhnGTt8jWGMm-mkyxCtX10YTKGD8ZsjYdzgcFHDhqrMjC1lZVAGHH1RjQwsAAgAA

Reproduction

To reproduce click the button and we expect to see the number inside the button increment through 0-5.

https://svelte.dev/playground/52b72be7ad104bfa91fe6fcaf475a63d?version=5.43.5

Logs

System Info

System:
    OS: macOS 26.1
    CPU: (16) arm64 Apple M4 Max
    Memory: 175.92 MB / 48.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.19.0 - /Users/away/Library/pnpm/node
    npm: 10.9.3 - /Users/away/Library/pnpm/npm
    pnpm: 10.20.0 - /Users/away/Library/pnpm/pnpm
  Browsers:
    Chrome: 142.0.7444.135
    Edge: 142.0.3595.65
    Safari: 26.1
  npmPackages:
    svelte: 5.43.5 => 5.43.5

Severity

blocking an upgrade

[dummdidumm]

Seems to be a regression caused by #17105