[AUCTeX] TeX-insert-macro-default-style not applied?

[Manuel Wiesinger]

Hi all,

When I set TeX-insert-macro-default-style to mandatory-args-only,
C-<RET> still asks me for optional arguments.

E.g. when entering \textcolor, AUCTeX asks for the optional color model
argument and inserts \textcolor[some_model]{some_color}{some_text}. With
TeX-insert-macro-default-style set to mandatory-args-only, I would
expect that I'm only asked for the mandatory color and text arguments
and that \textcolor{some_color}{some_text} is inserted.

Other macros show similar behavior.

I tried this with Emacs 26.1, on two machines and with a minimal config,
just loading AUCTeX.
Is this a bug, or I missing something?

Best,
Manuel