[Bug Report ID: #3948249541] Circular hole in floor texture

After clearing an Epitaph map (level 67 MapEpitaph seed 192222253), I noticed what looked like a circular hole in the floor texture on the far side of the final arena-like square (see bug report data for coordinates) - I can't be positive this isn't a puddle or similar sort of intended effect, but it looks unnaturally circular and feels more "see-through" rather than "reflection":