Hallo, and wishing you also a Happy New Year! I will reply in English to ensure I am clear, as my German is not technically advanced.

Most of this changeset focused on aligning paths and ways, and correcting some alignment issues with several houses and streets. I believe the issue with Route 638 (in beide Richtungen) occurs here: https://www.openstreetmap.org/relation/12717930#map=19/48.79399/9.05781 where Obere Ringstraße was split to reflect its actual shape.

I just checked the routing relation and it is laid down correctly on the street. So I guess this is not the issue. I made no other changes to the route other than those I thought were required to split the street and follow the direction correctly.

Please advise so I can make the necessary correction.

MfG dB