Derelict Mansion Boss bugged

Bug Report Reference Number: 1,628,750,537

In Derelict Mansion, I cleared 2/4 ritual altars. After clearing the 2nd ritual altar, two bosses spawned with red skulls on the mini map. I was able to kill one of the bosses, but the 2nd boss was unkillable in the ritual altar room. I walked around to the Arena, and now I am unable to leave the Arena, and I see the red skull standing just outside of the ritual altar room. The boss will not come into the Arena, and I cannot leave the Arena.