Is it a P3S? If so, Litchi says not to have both apps installed on the same device. Also, controlling your phantom can be done without any app at all. The RTH behavior is uploaded into the Phantom after you make the settings in the app. So you can make the settings in the app, then disconnect the device all together and still fly and the RTH functions will still behave as you set them in the app. So, if you had an issue with the RTH, it is likely that you have something set incorrectly, you didn't have enough satellites for a RTH or it was never initiated.
Also, RTH with Litchi can only be done with the button on the remote, the Litchi app has no RTH button like the DJI GO app does.