It's definitely a hex thing. but I can't seem to pin point exactly where, it may not even be in the objinfo or geodecl.
But I did kind of cheat and skirt around the problem by changing the body to another object slot altogether, so it's no longer subject to "special" rules"
I'm not sure if the results are something you even want for alpha anyway. looks more like a ghost than jelly.
I was hoping with a little bit a transparency used together with the slimy mtrcol would give a look more similar to that or the ---C file. could you test how it looks with about 10 to 25% transparency with the slime parameter? the slime parameter is
9A 99 99 3E 9A 99 99 3E 9A 99 99 3E 00 00 80 3F
00 00 80 3F 00 00 80 3F 00 00 80 3F 00 00 80 3F
00 00 C0 3F 00 00 C0 3F 00 00 C0 3F 00 00 48 43
9A 99 99 3E 9A 99 99 3E 9A 99 99 3E 00 00 80 3F
00 00 80 3F 00 00 80 3F 00 00 80 3F 00 00 80 3F
00 00 80 3F 00 00 80 3F 00 00 80 3F 00 00 80 3F
9A 99 99 3E 9A 99 99 3E 00 00 00 00 00 00 00 00
66 66 26 3F 66 66 26 3F 66 66 26 3F 9A 99 19 3F
9A 99 99 3F 00 00 80 3F CD CC 4C 3F 9A 99 19 3F
00 00 80 3F 00 00 80 3F 00 00 80 3F 00 00 80 3F
9A 99 19 3E 9A 99 19 3E 9A 99 19 3E 00 00 48 42
00 00 80 3F 00 00 80 3F 00 00 80 3F 00 00 80 3F
9A 99 99 3E 9A 99 99 3E 9A 99 99 3E 00 00 80 3F
or the glow one
9A 99 99 3E 9A 99 99 3E 9A 99 99 3E 00 00 80 3F
00 00 80 3F 00 00 80 3F 00 00 80 3F 00 00 80 3F
9A 99 99 3E 9A 99 99 3E 9A 99 99 3E 00 00 80 3F
00 00 00 00 00 00 00 00 00 00 00 00 00 00 80 3F
9A 99 99 3E 9A 99 99 3E 9A 99 99 3E 00 00 80 3F
00 00 80 3F 00 00 80 3F 00 00 80 3F 00 00 80 3F
9A 99 99 3E 9A 99 99 3E 00 00 00 00 00 00 00 00
9A 99 99 3E 9A 99 99 3E 9A 99 99 3E 00 00 80 3F
00 00 00 00 CD CC 4C 3E CD CC 4C 3D CD CC 4C 3E
00 00 80 3F 00 00 80 3F 00 00 80 3F 00 00 80 3F
9A 99 99 3E 9A 99 99 3E 9A 99 99 3E 00 00 80 3F
00 00 80 3F 00 00 80 3F 9A 99 99 3E 00 00 80 3F
9A 99 99 3E 9A 99 99 3E 9A 99 99 3E 00 00 80 3F
or if changing the body to a different object slot is a quick hex change, I could test it out myself