hdiutil burn: verify failed with but disc seems ok

I use hdiutil burn in a bash script called by a C program to make automatic backups (via popen-pclose). I also use mkisofs to make iso images to burn. The problem is that often hdiutil seems to burn fine the disc (the disc mount and run well) but it returns error on verify operation. I've tried changing disc brand but without changes. Drives info are: HL-DT-ST DVD-RW GWA-4165B C006. Any ideas?