References are often structured using templates such as Cite web or Cite book. When users edit such references, a specific form for such templates is shown instead of the general reference one in Visul Editor.
This was supported in Content translation (T199512), but a regression seems to have happened. Testing the same example checked in T199512#5049505 you can observe that the generic dialog is shown now for references:
Note that this ticket is specifically for references in the translation. The same issue for references on the source document is captured at T221241 and has some additional technical complications.