[Vanilla bug] Black screen in Mirror Dimension on macOS

Since Repentance+, accessing the Mirror Dimension in Downpour/Dross on macOS results in a black screen. The game continues to run (audio, input, etc.), but nothing is rendered. Isaac can still be controlled, and it is possible to return to the regular dimension, where everything renders normally.

This issue did not occur in the original Repentance release and has only been present since Repentance+. It has been known for a while (https://www.youtube.com/watch?v=TGDyUbVHbFU) and can be worked around by setting EnableWaterSurface=0 in config.ini. It occurs both with and without mods installed, including on a completely vanilla installation without Repentogon.

I understand this is a vanilla bug rather than a Repentogon issue, but I was wondering whether it might be something that could potentially be fixed or worked around in Repentogon.

Start by reproducing the black screen in the Mirror Dimension on macOS with EnableWaterSurface=1, then compare it with the config.ini workaround that sets EnableWaterSurface=0. The issue provides no source file, test, or entry point; done would require identifying whether Repentogon can affect this vanilla rendering failure and documenting a confirmed fix or workaround.