Try doing one with 'Immediate I/O' disabled in the settings - you might get a different error code as the drive then won't return control to the program until it's finished finalising - rather than ImgBurn polling to check if it's done and detect any errors.
What would be interesting actually is to capture the full error in the log. Next time you burn and it gets to the finalising bit (or just before it), press the F8 key to enable I/O debug mode.
Then if you could copy+paste the chunk of the log (or save and upload), I'll take a look at it.
ImgBurn *could* ignore these error at the end - which I bet most programs do - but that doesn't really solve anything. If there wasn't a problem, the drive shouldn't be reporting that there was.