Odd return behavior with std::function created from lambda (C++)

I'm having trouble with std::functions created from lambdas if the function returns a reference but the return type isn't explicitly called out as a lambda. It seems that the std::function is created fine with no warnings, but upon calling it, a value is returned when a reference is expected, causing things to blow up. Here's a very contrived example:

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

int main(){
   std::vector<int> v;
   v.push_back(123);
   std::function<const std::vector<int>&(const std::vector<int>&)> callback =
      [](const std::vector<int> &in){return in;};
   std::cout << callback(v).at(0) << std::endl;
   return 0;
}

This prints out garbage, however if the lambda is modified to explicitly return a const reference it works fine. I can understand the compiler thinking the lambda is return-by-value without the hint (when I originally ran into this problem, the lambda was directly returning the result from a function that returned a const reference, in which case I would think that the const reference return of the lambda would be deducible, but apparently not.) What I am surprised by is that the compiler lets the std::function be constructed from the lambda with mismatched return types. Is this behavior expected? Am I missing something in the standard that allows this mismatch to occur? I'm seeing this with g++ (GCC) 4.8.2, haven't tried it with anything else.

Thanks!