The supposedly bugfixed purple version of Judge doesn't seem to have been preserved yet.
Correct. Likewise, a bugfixed alternate version of (I think) Chef is also not preserved.
The good news is that the bugfixed version of Judge is in a different case color, and so should be relatively easy to track down if anyone is willing to put in the time. The bad news is that the bugfixed version of Chef requires opening the case and reading the marking on the chip package, which I doubt any seller would be willing to do.
I was aware of Judge and Helmet, what's meant to be fixed in Chef?
For Helmet, I thought we had the fixed version (or am I mistaken) so low serial number Japanese originals are probably going to have the buggy version.