1. Check that debug logging is enabled.
Open Sync settings -> Advanced, activate toggle "Debug logging"
2. Reproduce the issue
Please let Sync collect logs for at least 15 minutes to get enough information.
3. Click on "+" icon -> Enter key or link.
Type in "SNC.DBG.LOGS" and tap "Add". A hint "Debug action completed" should appear.
4. Collect the logs and send to support.
On Android device go to the root of internal storage and collect logs from the hidden .synclog folder. For example, full path is /storage/emulated/0/.synclogs.