One particular part of a trail (upper left) is not being rendered in full. Some of the segments are being omitted and therefore is being rendered in almost a straight line. However, if you view it with Osmarender or if you go to the Edit tab you will see the trail with all its segments. This does not happen with the rest of the trails
Definitely doesn’t seem to be anything wrong with the data, and I also queued the files for re-rendering and it came out exactly as before. I think you may have found a bug.
I’d suggest leaving it for a few days and see if anyone else has any ideas or drop a message onto the talk mailing list and see if anyone there has a clue and if not, it’s time for Trac.
There have been some subtle issues with diff files, and I guess we’ll have to wait for the next full planet to import to see if that indeed was the cause here as well.