Ah yes I found something: there is an additional 'CR' before the 'CR LF' sequence. It gets inserted automatically by a library function in the end, at a time when I already had created one manually myself...
I had verified the CR LF order some time ago when somebody reported a reversion error

, but the order has been correct all the time. The additional CR is ignored by most editors, so I did not notice that... the bug report description sent me in the wrong direction.
Thanks for insisting! I'll check the code for similar issues, the next version will include an improved version.