For now Greenify and 360 Security app have been identified as killing the app playback service way too often.
In that case make sure to disable those settings/apps in order to fix the issue.
If your device is running Android 6 or a more recent version, make sure that Podcast Addict isn't is the list of 'Optimized' apps. Optimized apps seem to be killed every xx minutes when in the background.
Please follow the steps below to do this:
1. Open the Settings app on your phone (Pull down the notifications shade, and tap the gear in the upper right corner, or find “Settings” in the App Drawer)
2. Tap Battery
3. Tap the menu button and choose "Battery optimization"
4. Tap the drop down menu at the top of the screen and select "All apps"
5. Scroll down to Podcast Addict, tap it and select "Don't Optimize"
This might be different for Samsung devices, so please check the screenshot here.