When you talk to a NPC, you should be able to see the biomes and other NPCs that this NPC love, like or dislike.
However, when I talk to Mutant, its favorite biome is something like "TownNPCMoodBiomes.Sky" with a question mark icon that looks like [?].
Have anyone met this issue? Did anyone fixed it?
The version is Terraria[1.4.3.6] with TModLoader on steam, Fargo's Mutant[2.8.7] and Fargo's Soul[1.4.1.2]. Also have Thorium[1.7.0.1] if that helps.