Insert into Global Temp Table

I am executing an INSERT into a global temp table.   If I execute the insert using a list of values (INSERT INTO gtt <...> VALUES <...>) then the insert performs successfully.  However, if I execute the insert using a SELECT statement (INSERT INTO gtt <...> SELECT <..>) then I get 0 rows inserted.  I have executed the SELECT statement by itself and confirmed that 1 rows is actually returned, so I would expect one row to be inserted into the global temp table when the INSERT is executed.   Is there something special that has to be done in order to