Thanks for the distinction and clarification. By thw way, I've just find 
that such issue occurs only with GUI Emacs! With Emacs running within a 
terminal (Konsole) everything works as expected, i.e. without any 
command-line arguments (oher than -nw) the prompt is transferred to the 
minibuffer.

On 25/12/20 21:59, João Távora wrote:
> I'm not 100% sure I follow, but just to underline what I said before: 
> if the system behaves as expected with -Q but not with
> lowercase -q then that clearly points to the system-wide shared 
> site-start.el file, not the user's init file.
>
> That's because '-q' inhibits the latter, but not the former.
>
> João
>
> On Fri, Dec 25, 2020, 21:46 Pedro J. V. Mendes 
> <pedro.mendes@ist.utl.pt <mailto:pedro.mendes@ist.utl.pt>> wrote:
>
>     In my system, only with―from man emacs―“
>                 -Q, --quick
>                           Similar  to  "-q --no-site-file
>     --no-splash".  Also, avoid processing X re‐
>                           sources.
>     ” is the prompt transferred to the minibuffer.
>
>     I'll check and tweak the startup configuration.
>
>     Thanks!
>
>     On 25/12/20 21:29, João Távora wrote:
>>     When I studied at that university, shared machines were a thing.
>>     I didn't know if they are still, but I'd also try with:
>>
>>     emacs -q # that's lowercase q
>>
>>     If the problem still happens, it's likely in the site-start.el ,
>>     and not in .emacs
>>
>>     https://www.gnu.org/software/emacs/manual/html_node/emacs/Init-File.html#Init-File
>>
>>     João
>>
>>     On Fri, Dec 25, 2020, 20:46 Daniel Martín via Bug reports for GNU
>>     Emacs, the Swiss army knife of text editors
>>     <bug-gnu-emacs@gnu.org <mailto:bug-gnu-emacs@gnu.org>> wrote:
>>
>>         "Pedro J. V. Mendes" via "Bug reports for GNU Emacs, the
>>         Swiss army
>>         knife of text editors" <bug-gnu-emacs@gnu.org
>>         <mailto:bug-gnu-emacs@gnu.org>> writes:
>>
>>         > OK, (only) after starting with emacs -Q does the password
>>         prompt (and
>>         > the focus) appear at the mini-buffer.
>>         >
>>
>>         Yes, that is expected.  The minibuffer prompt should hide
>>         your password
>>         with asterisks as you type it.
>>
>>         I think this may not be a bug in Emacs, but a problem
>>         somewhere in your
>>         Emacs configuration.  Comment out parts of your .emacs until
>>         you find
>>         the culprit.
>>
>>
>>