Its just that when i played build 12 there was no tentacles spawning in the cave (And the cave is massive), same for Iron as there was only crystal rods and coal.
Only when build 13 arrived i was finally able to get iron and see the tentacles and the traps (Yes there is more than just the traps in the cave as there was also supposed to be tentacle monsters)
But this means also that now there is no moths in build 13, even though its talked in the dev log.
A lot of the things that was supposed to be in build 12 is available in build 13.