Is Conversion 2 Useless for Nuclear Pokemon?

Conversion 2:
The user changes its type to make itself resistant to the type of attack the opponent used last.

I tried out Conversion 2 with my Nucleon, and it didn't have any effect.  If a Nuclear Pokemon uses Conversion 2, is it pointless?  I assume that they remain a Nuclear-type and thus maintain their weakness to the previous move-type.

So is it either useless or bugged?

I'm sure that I'm not the only one to have tested this, so I apologize if this has already been discussed  

I guess it's bugged, we included Conversion2 on Nucleon for that exact reason.

Should I test it again and then make a helpdesk topic?