This has been an ongoing issue for a while. This is why it is always better to cancel the original booking when possible, rather than modifying it. I was not able to get this issue resolved for 6+ months of trying last time I had this issue in 2019; the LH website was still not correct up to the day of flying, which caused a lot of stress on my end. The flights were ultimately OK, but the stress and hassle was definitely not pleasant.