" Are the filenames correct and am I doing something wrong, or are these bad ISOs?"
I would guess that these are bad ISOs. In Linux you can get the file names changed to DOS style file names if you do not have Joliet file extensions enabled. I don't know what operating system the CDs were created on but my guess is that somebody screwed up and did not turn on the Joliet file extension support in their OS.
You can also have the problem when reading CDs if you do not have Joliet file extensions in your system. In that case the file names are OK on the CD but only the DOS version of the file names can be read by your system. Since the first CD displayed OK then you have Joliet file extemsions set up OK. However you can turn the Joliet file extensions off when you mount the CD. Did you use nojoliet when you mounted the CDs? See:
Be prepared. Create a LifeBoat CD.