Same thing happened to me. Booked a ticket with CO, first flight FRA-IAH was on LH. I went to check in for that first flight online, noticed the UA*G was not on the online Boarding pass. When I got to the airport I had the check in lady change it to have my UA number, she told me that it had a Miles & More number on the booking, I told her to get that off there! It looks like the new LH online system addes the M&M number to all bookings that you enter on the LH page. She did add my UA number and my new boarding pass had the UA*G on it.. Miles for the LH flight went to miles and more, all the other flights op'ed by CO went to UA. I called M&M and they told me that I needed to fax (why they still use fax??) asking them to remove the miles. Then put a missing mile request with UA. I Faxed them 3 days ago.. the miles are still there.. I also emailed LH about this problem.