This is a longshot, but:

I had an older SCSI drive once which would not burn a CD after a while.
Updating the firmware solved the problem. My theory was the optical
components drift out of spec with age, and the newer firmware corrected for
that. Or maybe it was just media compatability. 8-)

So see if there is newer firmware.

Once burned, it reads the burned discs fine? I think that ll it does when
you insert it is to read the ATIP...