Hi Mathias:

It looks like your result file is a email nosy message.

Please view the message file in the roundup tracker home directory
under the db/files/msg/<prefix>/msg<msgid>.
Prefix the the first or first two digits of the message id.
Does the extra line spacing show up there as well?

I submitted file1746 to my running test tracker (modified with email
address of a tracker user and a different subject issue#) at:

  https://rouilj dot dynamic-dns.net slash sysadmin/issue1

(url mangled to prevent it from being hit by bots/indexers).

I didn't get any extra whitespace in the msg file, nosy email or web
interface. (If you view the url above, it uses a line height that adds
whitespace between lines. Try highlighting lines to verify that there
are no additional blank line.)

The mailgw settings are:

    [mailgw]
    keep_quoted_text = yes
    leave_body_unchanged = no
    default_class = issue
    language =
    subject_prefix_parsing = strict
    subject_suffix_parsing = strict
    subject_suffix_delimiters = []
    subject_content_match = always
    subject_updates_title = no
    refwd_re = (\s*\W?\s*(fw|fwd|re|aw|sv|ang)\W)+
    origmsg_re = ^[>|\s]*-----\s?Original Message\s?-----$
    sign_re = ^[>|\s]*-- ?$
    eol_re = [\r\n]+
    blankline_re = [\r\n]+\s*[\r\n]+
    unpack_rfc822 = no
    ignore_alternatives = no
    convert_htmltotext = none
    keep_real_from = no

that looks exactly like yours.

If I get a chance later today I'll spin up and configure a demo
tracker and see if I can reproduce with that. However my tracker
doesn't do anything special with message formatting so ...

I wonder if it has something to do with system locale or some such.
All my boxes are configured with en_US. Ralf, do you have a test
tracker using DE that you could test file1746 with
leave_body_unchanged=no.