I don't believe there is a high tech product sold today that perfectly performs the tasks it was designed to do, particularly any product that uses software to interface with consumers of that product. There are always bugs and different opinions on whether software is functioning correctly. The Phantom 4 is just a computer that also flies in the sky and can take pictures and just like Windows, there will always be "issues" with the way it does those things.
I have a
Phantom 4 Pro Plus - the RTH function is bullet proof, it flies when I want it to, it lands when I want it to and it goes from A - B whenever I want it to. As a bonus, it has a few functions like active track, POI etc, some work some don't. I'm happy.