Savannah Map Invisible fire patch

I was inside a brick wall room with only one entrance and I was standing in that entrance. There were not any mobs in that area. I looked away for two seconds and looked back to a "You Have Died" screen. When I went in there weren't any any fire patches nor any other puddles of death. I have a screen shot. I may do this wrong but here we go! https://i.postimg.cc/XvLKZmWW/Screenshot-2025-02-15-201814.png