Movie Render Queue PNG export always transparent

With Movie Render Queue and r.PostProcessing.PropogateAlpha enabled, I’m successfully exporting PNG sequences with alpha.

However, even when unchecking “Accumulator Includes Alpha”, the Movie Render Queue still removes alpha from all PNG sequence exports. Seems like this check box doesn’t do anything.

The workaround is to place an opaque black object in the background, but I don’t want my PNGs to contain the alpha channel if they do not need it.

Am I understanding this correctly? I would rather not disengage r.PostProcessing.PropogateAlpha every time I want PNGs without alpha, since it requires recompiling all shaders. I also don’t want to use JPG sequences due to the compression.

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