I do have issues with Illustrator displaying transparencies of placed PDFs as solid.
Steps to reproduce:
The topmost rectangle should be displayed with transparency.
The topmost rectangle is not transparent.
If you save the document with the placed PDF itself as PDF file, the rectangle is still transparent, so this is a display issue of Illustrator. Now it’s getting really weird: If you place this second PDF file in a new Illustrator document … all looks fine.
I am using Illustrator 25.0.1 on MacOS 10.14.6.
Placing in InDesign looks fine.
Placing as embedded in Illustrator looks fine.
Placing linked looks wrong, but turning on Overprint Preview looks correct.
You may want to mention it here:
I tried it in older versions and it looks fine.
After that I tried placing in Illustrator 2021 again and the problem disappeared.
It is a strange problem.
Hi Ton, thanks for making some more tests and the link to the feedback form. I have posted the issue there.
can you post the link to Uservoice here?
I found why it sometimes works and sometimes doesn't.
The CMYK PDF placed linked in a CMYK document gives the problem. Embedding solves the problem.
When the CMYK PDF is placed linked in an RGB document there is no problem.
The problem can be repeated in older Illustrator versions.