Last night I spent some time with this bug. The problem is it takes several hours to reproduce and hence I get just one iteration a day. But what I found is that the reason the MD5 checksums do not match is that the SW was unable to find a file on the ISO file system because it was no longer mounted!
During disc creation I create the ISO image using mkisofs. After the files are added, I mount the file system as a loop and double check the integrity of the file system by performing an MD5 checksum test against the original file. At the point the break point hit when a file did not match, I found that the file system was no longer mounted! Poof it was gone. The ISO image was still in the temp directory, but it was not mounted.
What could cause that? Too big a file? Some Linux error (need to check /var/log/messages). Some permission issue (but this runs as root!)? And why to the previous 70,000 files work and it only barfs at this point? Does it always barf on the same file or perhaps after the same amount of time? What processes would un-mount a loop file system?
“This is not fair!”