Movie Render Output resolution does not match Filmback aspect ratio

I’m getting an Unexpected size error while trying to render with an output resolution of 2222 x 1170 given a Custom Filmback of 36.700001 mm x 19.32 mm (aspect ratio 1.899585)

LogMovieRenderPipeline: Unexpected size in FMoviePipelineSurfaceReader::CopyReadbackTexture_RenderThread.
LogMovieRenderPipeline: Expected size: 2222 x 1170
LogMovieRenderPipeline: Actual size: 2240 x 1170

1170px x 1.899585aspect = 2222.51px. Where is the “Actual size” 2240px coming from? 2240 x 1170 implies an aspect ratio of 1.914529 not the actual 1.9 (1.899585) selected. Even if the system is rounding the aspect to 1.9 the horizontal resolution should be 2223px not 2240 .