SQL Server Trace Stopped Messages Displaying Random Login Name
Found an answer here: http://www.360sqldba.com/2015/08/sql-error-log-shows-random-user-and.html

Conclusion: SQL error log message about which user and SPID stopped a timed trace is misleading. It appears that SQL uses a random active session to stop timed trace. It may be something that MS SQL team overlooked.