Please help us by providing the following info.
Steps to reproduce
1. Set any folder in ownCloud app as "Available Offline"
2. Go into any other application or the home screen
3. From another device or computer add items to that same folder
4. Nothing happens on the Android device
5. Open ownCloud app and then it realizes things need to sync and all is fine
One would expect a background task to check for changes to folders that are marked "Available Offline" and automatically sync them once in a while without having to manually open the app. Be it once per hour or what ever. (user defined would be best if it can't "sense" the change)
No sync happens until the app is manually opened again.
Mobile client configuration
Client OS Android
Client version: 6 & 7
Operating system: Linux
Web server: Apache
PHP version: 7
ownCloud version 2.3.0