Have there ever been silent behavior changes in C++ with new standard versions?

The return type of string::data changes from const char* to char* in C++ 17. That could certainly make a difference

void func(char* data)
{
    cout << data << " is not const\n";
}

void func(const char* data)
{
    cout << data << " is const\n";
}

int main()
{
    string s = "xyz";
    func(s.data());
}

A bit contrived but this legal program would change its output going from C++14 to C++17.