This disc is very likely a hacked dump (not sure why someone would do that...)
1) The comments reference PZHP as an internal serial, which is true but that doesn't align with the other regional variants of this game which is highly suspicious
2) The differences between the alt version and regular version are 3 bytes, which are just the disc id in the header
3) The junk data present on the disc is indeed generated using GNDP as an input and not PZHP
4) Disc serial does not match the internal serial
5) There are no other GC games that have Alt versions. GC game versions are clearly identified in the mastering code.
6) No ring codes submitted with this dump
Unless there is proof or someone has more info about this disc it should be marked yellow or removed entirely.