Seing multiple 0xaa is a sign of using uninitialized pointer from an lv_obj, as lv_mem_alloc() memsets the freshly allocated space by 0xaa #if LV_MEM_ADD_JUNK.
Indeed, lv_refr.c:517 is
obj->design_cb(obj, &obj_ext_mask, LV_DESIGN_DRAW_MAIN);
so it’s an attempt to refresh an object which hasn’t set design_cb.
Evan, can you please show us what are you trying to draw?
JW
PS. Reminded me of what have I seen when investigating Lv_tabview_create() with copy does not initialize ext->tab_cnt