Writer: (macOS) Save as PDF fails to render area bitmap transparency - always fully opaque

macOS Sierra 10.12.4

Writer odt documents containing Area (Format>Page>tab) bitmaps (button) with a specified Transparency (Format>Page>tab) do not render to PDF correctly.

This looks like 95% transparency ( very faint watermark) being interpreted as 95% opacity (very heavy watermark) when rendering to PDF. The LO display is correct on macOS - 95% transparency is very faint.

Is this fixed in any earlier or later version ?