it just puts blocks where the capstones would go and then says obstructed
https://imgur.com/a/L2iqjtU

http://prntscr.com/jge55e
Tier 6 NYI

I know its not in yet but the altar diviner places 4 blocks out at the t6 capstones and creates a ghost image of it which is intuitive behavior, I was thinking maybe just dont have to render the t6 altar at all until its implemented