I have noticed colours not displaying correctly when overprinting. It is happening on images, blocks of colour, everything.

It seems that Cyan won't overprint Cyan. Magenta won't overprint Magenta. Yellow won't overprint yellow.

I've tried all the colour profiles but that doesn't help. I have created a pdf from InDesign to illustrate the issue. The stars point to the incorrect overprints.

I believe it is also happening in Illustrator.

I updated my apps hoping that might help but I have the same problem on the latest versions.

I've working in printing for a long time and this seems like it might be a bug.

Using Indesign version 20.1.0.