Serial number in warranty claims throws an error

When I choose a serial number in warranty claim, I get this error "pymysql.err.OperationalError: (1054, “Unknown column ‘tabSerial No.customer’ in ‘where clause’”)
In github, issue# 38394 it says the issue is completed and closed. but I am still encountering the same error message.
Any update on how to fix this. I am using ver erpnext v15. Thanks