What steps will reproduce the problem?
1. On Opencaching.de, add a personal note _and_ self defined coordinates to a 
cache (e.g. to a mystery).
2. Run a geocache OKAPI query for that cache.

What is the expected output? What do you see instead?
The personal note is in the JSON response, the self defined coordinates are 
not. In contrast to that, both the personal note and the self defined 
coordinates are contained in the GPX file for the same cache.

I've discovered this using c:geo. Right now, we always recommend c:geo users to 
edit GC mystery final coordinates directly on the geocaching.com website. That 
way they will always be correct, if they download the cache to different 
devices with c:geo. It would be nice if we could give opencaching users the 
same recommendation, but right now c:geo does not get this own coordinate from 
the website.