Lv_obj_get_disp returning NULL which causes Dereference null segfault

Followup from previous post here: Dereference null segfault when calling lv_obj_create

lv_obj_get_disp returns NULL when being called in a sub-class function, see psuedocode below

funcA( screenptr ){
// lv_obj_get_disp(screenptr) does NOT return NULL here
funcB( screenptr );
virtual funcB( screenptr ){};

subClass extends superClass{
funcB( screenptr ){
// lv_obj_get_disp(screenptr) returns NULL here

I can’t call most of lvgl libraries without crashing because almost all object creation/object interation functions involve calling lv_obj_get_disp. If anyone familiar with lvgl screens/displays could give some pointers, I’d appreciate it!