This is a scripted encounter for a Ancient Dungeon with the reward of Spider Boots and listed as Deadly.  The quest card says it was called "The Capstone."   If you proceed the next scripted bit places spider units on the strategic map then the tactical map for the combat loads.  Inside the combat event the 1st unit to act is the Hoarder Spider and she casts Summon Spiders.  This spell sticks each time and the combat cant proceed. The active unit grey box stays active on the Hoarder Spider.  The game does not freeze and you can click the units to bring up their information cards.  The music still plays and you can push the Debug button to see that a bunch of tiny events are running but nothing else happens.  The combat wont complete for me; I tried it 4 times.