I also had a sound problem Android 13 phone connected to car via Android Auto and Screen2Auto , iGO_Basar_9.18.27.736574.
When iGO sounded, the Radio turned off. And you couldn't listen to the radio while using iGO navigation.
No changes to sys.txt helped.
The solution to the problem turned out to be: deleting the save folder, deleting the sys.txt file, reinstalling iGO.
Now the radio mutes as there is a message from iGO, after which the radio volume returns to its level. Eventually everything is OK.