It was a default watchtower that spawned on Elderlicht.
Day 1 Production phase.
After the crash I have returned to the start of the day again. Interestingly I got the same night rewards but getting different level up rolls.
#Putting a hero into a watchtower during daytime crashed the game
barren gulch
pastel root
if you have your save you can share that might help the devs as well