[Bug]: "ON THIS PAGE" is displayed on overview page inconsistently after v2.0.0-rc.1

[JounQin]

Version

System:
    OS: macOS 26.1
    CPU: (10) arm64 Apple M1 Max
    Memory: 4.85 GB / 64.00 GB
    Shell: 5.9 - /bin/zsh
  Browsers:
    Chrome: 142.0.7444.176
    Firefox: 145.0.1
    Safari: 26.1

Details

For screen <1280px:

For screen >=1280px:

Reproduce link

https://v2.rspress.rs/api/

Reproduce Steps

As above