Why is it opening .PPT/X in Draw instead of Impress?

Windows 7 SP1, LibreOfice 5.2

I have some files that are .PPT and .PPTX that ought to open using Impress, but somehow it is redirecting the files to Draw! I have tried setting the default app, opening from Impress, and also click and drag the files from desktop to Impress, but it is always Draw that opens them.

Did not find a solution on Google. Is anyone else experiencing this?

A test file required, and if that’s reproducible (i.e. not some corrupt install/profile), bug report.