To reproduce:

• Go to French Wikiversity appearance preferences.
  • Select Timeless skin.
  • Make sure that the "Utilisez une liste compacte de langues, avec celles qui vous concernent." preference is checked (it's the last preference in the "Apparence" tab).
  • Save the preferences.
• Go to the French Wikiversity main page.

Observe: The compact language list has an unnecessary scrollbar. There's nothing to scroll, because the list is already compact.

If you're testing this on another wiki, note that the UniversalLanguageSelector extension must be installed, and the Compact Language Links feature must be enabled.