I'm using the latest version of CCleaner, and I'm still facing this issue. Alan, I didn't have this issue a few months ago, and I haven't changed the drive's firmware. I'm using a hard disk, not SSD.
I was suspicious when it jumped from 33% (with it set to 3 passes) to saying it was complete, so I tested it with a virtual drive, which let me look at how many bytes had been written. I only have this problem on my desktop; on the laptop, CCleaner does all the passes.
Even if I have it set to do 3 passes (or 7), the drive wiper only completes one of those passes; once the first pass is done, it sas "the drive wipe has been completed successfully."