C++ :: Vector Iterators Incompatible In Debug Mode

I get this error when i try to run this code for an inventory in debug mode in VS. But for some reason it works just fine in release mode.

void Push_Back_Item(Item *item){
for(int y = 0; y < InvSizeY; y ++)
for(int x = 0; x < InvSizeX; x ++){
auto Iter = ItemList.find(std::make_pair(x,y));
if(Iter != ItemList.end()){
item->SetDead(); // ERROR
}
}
}

This isnt the full code though but it still gives me the same error.

The only thing "item->SetDead()" does is to set a bool to true.

This is the map i get the iterator from
std::map<std::pair<int,int>,Item*> ItemList;

This have been bugging me for quite some time now.