PreviewApp displays transparent items in PDF wrongly

Strangely, the Preview app displays an image with transparency inconsistently compared to Adobe Acrobat.

How to reproduce:

• Create a slide with a transparent image in PowerPoint (Desktop app, for MacOS)
  • Create new document
  • Insert image
  • Set transparency to 60%
  • Save the document as PDF
• I yield the attached following test.pdf

WRONG: If I look at it in the Preview app, the image looks distorted (gray).

CORRECT: If I view the same PDF file in Adobe Acrobat, the image is displayed correctly and matches the appearance of the image in the PowerPoint application.

Where does this inconsistency come from?

Below is the original image I've been working with.