Yeah, saying tengu mask would make sense, because tengu are crow demons, and that would relate to the conversation they were having with the crow being present. Calling it a goblin mask doesn't relate to the crow, and doesn't make sense. Disappointing mistranslation.
I believe tengu are sometimes referred to as "Japanese goblins", so while it would have made more sense to just make the subtitles say "tengu" i guess it's not entirely incorrect but still a bit loosely translated
thats not true. A tengu is also called a bird demon or bird yokai not Japanese goblins. I think the translator probably thinks that western audience doesnt know what a tengu is, so they pick goblin so that western audience can understand it
Tengu in general is a type of mountain and/or forest Goblin, like a Goblin sub-class. It is not necessarily a bird youkai as there are other types, although the most common Tengu is the Karasu Tengu which is directly translated in English as Crow Goblins. So the translation is not exactly wrong as it was not confirmed what kind of Tengu is the Master's mask. Maybe it really was a Crow Goblin as it common.