Nessa and part of Brine King model appearing during Kitava fight

Hey, bit of a weird one.

I was fighting Kitava (act 5) using a fire damage build and noticed something weird. There were weird objects around the base of Kitava's model. When Kitava finally moved to one side far enough, right there, clear as day, was Nessa's mermaid model, and the objects around Kitava's base are, I'm pretty sure, the Brine King's legs.

In trying to get a screenshot, I noticed the extra model would disappear after the Scorching Ray debuffs fell off. Not sure if it was the burn DoT or Fire Exposure, but it seemed linked to one of them. Despite that, I did manage to get a screenshot of it. I can provide the screenshot if you want, but it might be reproducible just by using Scorching Ray on Kitava.