Well... We may (or may not) have another issue here. This was the original
paragraph (taken from the source, the space is indicated with "[20d]"
below):

---------------------------------------------------------------------
> Mal was ganz anderes zwischendurch: Es ist ja jetzt bei der Telekom[20d]
> die Rede
> davon, zuk=FCnftig ab einer bestimmten Datenmenge den Durchsatz zu[20d]
> drosseln.
---------------------------------------------------------------------

Note that there is NO space after "Rede" in the second line. So upon
replying, the paragraph will correctly be loaded in the plain text editor
this way:

---------------------------------------------------------------------------=
----
>> Mal was ganz anderes zwischendurch: Es ist ja jetzt bei der Telekom die =
Rede
>> davon, zuk=FCnftig ab einer bestimmten Datenmenge den Durchsatz zu dross=
eln.
---------------------------------------------------------------------------=
----

Note that there is still no space after "Rede", which is correct.

And it will be sent this way with format=3Dflowed (again, space is indicate=
d
with "[20d]":

---------------------------------------------------------------------------=
----
>> Mal was ganz anderes zwischendurch: Es ist ja jetzt bei der Telekom die[=
20d]
>> Rede
>> davon, zuk=FCnftig ab einer bestimmten Datenmenge den Durchsatz zu dross=
eln.
---------------------------------------------------------------------------=
----

So all correct so far (although I don't know why "Rede" is wrapped to the
second line, but due to the space at the end of the previous line, the
format appears to be correct).

BUT:

If I deliberately ADD a space manually right after "Rede" this way in the
editor, to deliberately make it a "full flowed" paragraph...

---------------------------------------------------------------------------=
----
>> Mal was ganz anderes zwischendurch: Es ist ja jetzt bei der Telekom die =
Rede[20d]
>> davon, zuk=FCnftig ab einer bestimmten Datenmenge den Durchsatz zu dross=
eln.
---------------------------------------------------------------------------=
----

=2E..THEN the [20d] right after "Rede" will be eliminated upon sending!?

Not sure if this is by design, but I wouldn't know why. If spaces at the en=
d
of a line do indeed apply to (the quote of) quoted paragraphs as well, then
this appears to be an issue.

Tested with 8bit and qp, no difference.