I dont know if this will help but i was browsing around on go 4 app latest version dowloaded from dji.com and found these settings that could be responsible for the drain. Hope this wasnt posted before, but i browse these forums frequently and havent seen anyone mention these settings. The setting i have unchecked could be the culprit. Its found under the me tab then go to settings.

I have the bottom one on but I don't get any adverse battery drain from the app.