I was traveling there with OSMand, it includes a setting to show the height lines. I already got the info where I could report this issue (either the issue tracker or directly at NASA, which supplied the data in their program; probably the first one). See https://osmand.net/blog/Elevation, and the bottom for the license.

This issue is not related to OSM; I just had no other way to report the problem on the go. Therefore I added 'OSM data is correct' in my statement. I will keep the note open to know where that issue with the height lines was.