Hi all,
Today I ran into the same problem. On GC.com I have 8 Friends I follow. After signing on in the Cachly app, only 2 of them showed up.
I contacted one Friend to test things out. On https://www.geocaching.com/account/settings/authorizations we both checked the "Allow Authorized Developer Applications to share your geocaching activities with your Geocaching.com friends":
Unfortunately nothing changed; he didn't show up in my Cachly, I didn't show up in his'.
Then we found another setting on https://www.geocaching.com/account/settings/preferences. After checking "Show my activity on my friends' Dashboards" we showed up in each others Friendspage in Cachly again: