When any entity with a helmet on it is loaded it breaks the rendering of all nearby entities, including liquids. This bug was present on all the 1.12.2 versions I tested (v0.09b, v0.0.10b, v0.0.10d, v0.0.11b, v0.0.12a, and b, as well as v0.0.1.b), but was not present in the 1.16 versions
Video using an armor stand for easy demonstration:
https://youtu.be/lB3hdWjpCEg