I managed to figure it out, IDK the low-level specifics but basically since updating world objects happens in the middle of a for() that reads the vector, it would see the new object get added to the end of the vector and try to call it's updateMe() while the vector was getting shifted around. Adding a lag of one game tick before each new object spawns by giving them a queue to wait in helped work around the issue. So I just do this before each tick:

for (globals::objects::o_worldObjectGeneric* o : w_contentQueue) w_content.push_back(o); w_contentQueue.clear();