There might be spawn issues that I'm not aware of. Well, now I am. The Moth is located in a cave in a pretty visible spot, right before the bridge.
If something didn't spawn, the simplest fix is just to reload the world or restart the game.
Viewing post in Update Build 13 (The Moth) is here! comments
If Cave you mean the cave near the mushroom people, where the twins live in the cave, then yeah there is only tentacle women and those tentacle traps. No Moths.
This was the same problem in build 12.
No Tentacles and there was no iron.
And pretty sure there was also no twins in build 12.
I would not be surprised if build 14 has the Moths when it arrives. (Unless Build 13 gets fixed)
And yes, i did everything. From deleting local files to restart game, everything. There is just no Moths in this update.