I loaded a GPX file generated with GSAK, mostly full of mystery caches with corrected coordinates, and noticed that two of the caches were being displayed at the south pole on the map, instead of being shown at their correct locations. When viewing the list of caches, the distance was reported as 7000 miles or some huge number. If I navigate to one of these caches, it displays in the right place, but one of the waypoints is shown at the south pole. This waypoint is displayed on the website but its coordinates are hidden, so it probably shouldn't be displayed at all. If I refresh these caches, the problem goes away. If I delete the corrected coordinates from GSAK (but leave the bad waypoint) and make a new GPX, the new GPX works.
Cachly 3.0.3 (14) on a iPhone X running 11.1.1, and I can send you the GPX