SUMMARY

While saving a file, Lokalize behaves some odd in comparison with other translations editors. For all multiline strings (which are dynamically wrapped at 80 characters as usual) a whitespace character gets not placed at the end of a wrapped line, but at teh beginning of the next one.

STEPS TO REPRODUCE

1. Open a po file which has some already translated multiline strings. 
2. Change one of that strings.
3. Save the file.

OBSERVED RESULT

All strings changed by Localize get the whitespaces at the beginning of the line, like in the following string:

#. type: Plain text
msgid ""
"When writing scripts that need to decompress files, it is recommended to "
"always use the name B<xz> with appropriate arguments (B<xz -d> or B<xz -"
"dc>)  instead of the names B<unxz> and B<xzcat>."
msgstr ""
"Beim Schreiben von Skripten, die Dateien dekomprimieren müssen, wird es"
" empfohlen, immer den Namen B<xz> mit den entsprechenden Argumenten B<xz -d>"
" oder B<xz -dc>) anstelle der Namen B<unxz> und B<xzcat> zu verwenden."

EXPECTED RESULT

The whitespaces should be at the end of the lines. The same string as above after launching "msgcat -w 80":

#. type: Plain text
msgid ""
"When writing scripts that need to decompress files, it is recommended to "
"always use the name B<xz> with appropriate arguments (B<xz -d> or B<xz -dc>)  "
"instead of the names B<unxz> and B<xzcat>."
msgstr ""
"Beim Schreiben von Skripten, die Dateien dekomprimieren müssen, wird es "
"empfohlen, immer den Namen B<xz> mit den entsprechenden Argumenten B<xz -d> "
"oder B<xz -dc>) anstelle der Namen B<unxz> und B<xzcat> zu verwenden."

I don't know if it's essential for the compatibility that the files are not fully canonical (in comparison with Poedit or Gnome Translation Editor), but the effect of a basic command line tool like msgcat shows me that it's at least a bit strange. Maybe it could lead to undesired behavior in other environments which parse *.po files.

SOFTWARE/OS VERSIONS 
Linux/KDE Plasma: Kernel 4.20.0 (Archlinux)
KDE Plasma Version: 5.14.4
KDE Frameworks Version: 5.53.0
Qt Version: 5.12.0
Lokalize Version: 18.12.0

ADDITIONAL INFORMATION