I’ve confirmed the following:
1. Creating an options page, then changing the title/menu name options does break the page<->field group link. Revisiting the field group and updating it re-associates things correctly.
2. Adding a ‘slug’ argument breaks things completely. The behavior in #1 would be expected, however upon updating the field group those fields still do not show up in the options page. Even if I add a ‘slug’ argument before creating a new field group there still seems to be no association between the options page and field group.
