While new production of commercial MBS continued to grow gradually during the third quarter, some market watchdogs are raising questions about growing risks in the sector. New issuance of commercial MBS edged up 4.6 percent in the third quarter, hitting $24.9 billion, according to data compiled by Inside MBS & ABS. That brought year-to-date issuance to $71.94 billion, up 26.1 percent from the same period in 2003. …