Special:GlobalPreferences does not deal well with "conditional preferences" (using hide-if). When a preference is hidden because the conditions to show it are not met, the checkbox to set it as global is still visible.
Currently this affects two preferences (testing on https://en.wikipedia.beta.wmflabs.org/wiki/Special:GlobalPreferences):
{nav User profile > Newcomer homepage > Default to newcomer homepage from username link in personal tools} (only shown if {nav Display newcomer homepage} is checked)
{F31649477 layout=inline} {F31649488 layout=inline}
{nav Appearance > Vector skin preferences > Use Legacy Vector} (only shown if {nav Skin > Vector} is selected)
{F31649480 layout=inline} {F31649485 layout=inline}
== QA Results - Beta|Prod
| **AC** | **Status** | **Details** |
| ----- | ----- | ----- |
| 1 | ✅ | T246491#6370891 |