I've added one new translation string to a program and ran a "git diff" on the "messages.po" file - just to see if everything looks good.
I suddenly saw more differences than the one string I've changed.
And the affected translations all started with:
[SOLUTION]msgstr ""
Everything perfectly normal.
The new Poedit version was just set to automatically wrap the "message.po" at 79 characters (see screenshot).
The empty msgstr line (as well as additional msgstr lines for the same string) are just to avoid more tha 79 characters per line.
Mystery solved
