Should the MV-HEVC Encoder Support Multiple Passes?

As a straightforward example, I've taken Apple's MV-HEVC sample project and added two lines.

First, after the AVAssetWriterInput is created:

frameInput.performsMultiPassEncodingIfSupported = true

Second, after the call to multiviewWriter.startWriting():

print("canPerformMultiplePasses: \(frameInput.canPerformMultiplePasses)")

Which prints true.

This leads me to believe that the first encoding pass should proceed as-normal (even though I haven't handled the logic for the completion of the first pass, etc.).

However, I receive this error when the code attempts to appendTaggedBuffers to the AVAssetWriterInputTaggedPixelBufferGroupAdaptor:

Fatal error: Failed to append tagged buffers to multiview output

Am I missing a step? Or is the multi-pass encoding only supported for standard sample/pixel buffers (and not tagged buffers)?