Reported on support mail:

Bug report for you. This is the most ambitious and maybe one of the more sophisticated wherigo cartridges I've come across. Naturally, that means it's also prone to crashes and other malfunctions.

Coree Clamber
https://coord.info/GC1KHW3

https://www.wherigo.com/cartridge/details.aspx?CGUID=0b8e7940-7a39-408f-83a1-411f3d948d96

I have a couple screen shots with crash reports (I'll forward them if you think you really need them), but for the time being I'll leave it with you to have a poke around. You should have no trouble finding the source of the errors, not least of which is a reliance on altitude.

For what it's worth, this particular wherigo involves a long hike in some pretty hairy places. I ran the cartridge using a GPS emulator in the hope of extracting the 14 waypoints (for safety sake) but because my phone does not handle altitude it was no help. Still, I think this one might be worth your time to strengthen your already solid program.