This does appear to be a design failure, as 205.3h includes Shrine as an enchantment type, however these appear to be the ONLY enchantment creatures that do not have a creature subtype.
Indeed, I believe these are the only creatures without a type in standard. (Nameless Race all the way back in 'The Dark' and facedown Morph creatures being the only other exceptions I can think of).
March of the Machines and Starfield of Nyx could also cause this effect, although they would not cause this specific issue.
Edit:
Reconfigure creatures DO appear to all also have a creature type in addition to the 'Equipment' artifact type.
@Moocow17 @WotC
This does appear to be a design failure, as 205.3h includes Shrine as an enchantment type, however these appear to be the ONLY enchantment creatures that do not have a creature subtype.
Indeed, I believe these are the only creatures without a type in standard. (Nameless Race all the way back in 'The Dark' and facedown Morph creatures being the only other exceptions I can think of).
March of the Machines and Starfield of Nyx could also cause this effect, although they would not cause this specific issue.
Edit:
Reconfigure creatures DO appear to all also have a creature type in addition to the 'Equipment' artifact type.