Iterator validity

I'm looking for a more in depth explanation here, not just how to get working code. I know how to write much shorter code to erase elements. I wrote this test code here to pinpoint points of failure upon deletion. It would seem that not only the i iterator becomes invalid but also the .end() iterator... and that is interesting.

Why is that this works?

auto end = data.end();
for(auto i = data.begin(); i != end;)
{

    if( (*i)->getName() == "apple" )
    {
        auto ti = i;
        ++ti;
        end = data.end();   //above erase, works but not logical
        data.erase(i);
        i=ti;
    }
    else
    {
       ++i;
       end = data.end();
    }
}

but this does not work?

auto end = data.end();
for(auto i = data.begin(); i != end;)
{

    if( (*i)->getName() == "apple" )
    {
        auto ti = i;
        ++ti;
        data.erase(i);
        end = data.end();   //Bellow erase...more logical but crashes
        i=ti;
    }
    else
    {
       ++i;
       end = data.end();
    }
}

I'm guessing that there is dome implementation level issue here. Perhaps a compiler bug. Using GCC 4.8.2.