Ordering issue while popping from priority_queue, Is this a bug with std::priority_queue

#include <functional>
#include <queue>
#include <vector>
#include <iostream>

 struct Temp
 {
   int p;
   std::string str;
 };

 struct TempCompare
 {
     bool operator()(Temp const & a, Temp const & b)
     {
         return a.p > b.p;
     }
 };

int main() {

    std::priority_queue<Temp, std::vector<Temp>, TempCompare> pq;
    //Enable and Disable the following line to see the different output
    //{Temp t; t.p=8;t.str="str1";pq.push(t);} 
    {Temp t; t.p=8;t.str="str2";pq.push(t);}
    {Temp t; t.p=9; t.str="str1";pq.push(t);}
    {Temp t; t.p=9; t.str="str2";pq.push(t);}

    while(!pq.empty())
    {
        std::cout << pq.top().p << " " << pq.top().str << std::endl;
        pq.pop();
    }
}

Run the above program with enabling and disabling the fourth line in main; The output you get when its disabled is

8 str2
9 str1
9 str2

whereas when its enabled you get

8 str1
8 str2
9 str2
9 str1

Shouldnt the behavior shall be consistent?