I asume with “My app” you mean Litchi?
and with “Note8 - updated to the latest version” you mean Litchi as well?
Litchi does not delete itself.
Possible causes:
- Malware on the device
- Not enough free memory
- Too much apps active in the background
- ???
Solutions:
- Check for malware with a virus scanner
2a. Free up space by uninstalling unused apps
2b. Clear Litchi’s Cache and/or Data - Force Close all apps before starting Litchi