DepthFormat.Depth24Stencil8 is not working on iOS MonoGame

I have been using this popular guide to do stenciling onto a RenderTarget2D. This has been successful on Android, but when the same code is run on iOS nothing drawn to the RenderTarget appears.

If I change the DepthFormat of the RenderTarget2D to Default then my content is rendered, but without the stenciling.

Creating the RenderTarget2D:
renderTarget = new RenderTarget2D(graphicsDevice, width, height, false, SurfaceFormat.Color, DepthFormat.Depth24Stencil8, graphics.PresentationParameters.MultiSampleCount, RenderTargetUsage.PreserveContents);

Is there a known limitation for DepthFormat.Depth24Stencil8 on iOS? Should this be working?

Thanks,
Tom

I have submitted this as a new issue on github with repro steps.