Using RenderTexture Twice Clears the Previous Contents of the Texture (iOS only)

I'm running into an issue with RenderTexture, on iOS-only builds.
I am doing a 2-pass render to the RenderTexture from 2 different cameras (code below).

The first pass looks like this:


But on iOS, the second pass looks like this:


The second pass completely obliterates the first pass.
I do not have this...

Using RenderTexture Twice Clears the Previous Contents of the Texture (iOS only)