Crash when replacing std::map value

I have this map

std::map<IPv4Address,std::vector<Agent>> report;

Where agent is defined as the following

typedef struct
{
    IPv4Address Address;
    AgentType Type;
    std::map <IPv4Address, IPRoute> RoutingTable;
    MetricType metric;
    int UpdateReceived = 0;
}Agent;

I am sending this Agent struct through tcp sockets and saving the values in the report std::map

int receive = recv(as.socket, (void *) &agent, sizeof(agent),0);

The routing table is initially empty and there is no problem, but when the routing table size becomes >=1 the app crashes when adding it like the following

             mutex.lock();
             PrintInfo("Mutex locked");
             if(report.find(as.ip) != report.end())
             {
                 //f tells us if the agent was connected before to the router
                 bool f = false;
                 std::vector<Agent> tmpv =report[as.ip];
                 int tmp;

                 PrintInfo("Vector loop");
                 for(std::size_t i=0 ; i < tmpv.size() ; i++)
                 {
                     if(tmpv[i].Type == agent.Type)
                     {
                         f = true;
                         tmp = i;
                         break;
                     }
                 }

                 PrintInfo("Vector loop End");

                 if(f)
                 {
                     PrintInfo("Found -> Replacing");
  --> This line crashes  report[as.ip][tmp] = agent;
                 }
                 else
                 {
                     PrintInfo("Not Found -> Adding");
                     report[as.ip].push_back(agent);
                 }


                 PrintInfo("After add");
             }