Purple And Blue Quest Bugged (I think)

I started the purple and blue quest, got to stage 6.
Where is Korun's basement? Am I supposed to enter the cave at -140 27 -5270? Because if I'm supposed to, its bugged and I cant enter it even while wearing the Empowered Ancient Helmet, nor a Dull Ancient helmet (I got another one).
Also my Empowered Ancient Helmet is bugged, its not a quest item but I cant drop it.
Please help

 

not sure what cave you're referring to but korun's basement is via a ladder in the floor right next to him
and about the helmet, i'd assume that's intentional since you can't repeat the stage for korun to give you another, dunno why it doesn't say it's a quest item though

 

thank you!