Your logs show Symfonium restarting after Android stopped it, then restoring the previous track in a paused state. This is consistent with the Samsung media-session restoration behavior, and explains the controls appearing without music playing. I’ve discussed similar behavior here: Media session notification being bumped to front even when not in use.
Please enable Disable media session restoration in Symfonium’s settings. This prevents restoring those paused controls on startup, but disables quick resume, so it may affect resuming music from your car.
Your logs are from 15.0.1. Please also update to 15.1.0 and try again. Read the release notes and APK instructions; if Google Play has not approved that release yet, its announcement explains how to get the official APK.
If the controls still reappear after updating and enabling the setting, please send fresh debug logs. Enable debug mode before reproducing the full sequence, then disable it and upload promptly. Reply with the app version, upload description and the time the controls appeared so I can match the event.