certain PDFs with an image layered below a mask layered below text, ignore the mask

[caribet42]

SumatraPDF version

• Version 3.5.2

Describe the bug
I have received a couple of PDFs which render correctly in Adobe, Foxit, Brave/Chrome, etc.
If Sumatra, they don't.
Each problem page has an image which extends over much of the page and below much of the text, but when rendered correctly that image should be masked/clipped so that most of the image does not show.
In Sumatra, it incorrectly shows the whole image.
The fault survives compression by ilovepdf.com

To Reproduce
Steps to reproduce the behavior:

1. Open attached PDF, go to page 2 or page 7
2. Page 2 is best - the text is very hard to read because of the image beneath the text

Expected behavior
Open in Adobe or Foxit or Chrome. Look at same page. Not the visual difference.

File that reproduces the problem
The prophecies of the professor_compressed.pdf

Screenshots
If applicable, add screenshots to help explain your problem.

Additional context
Add any other context about the problem here.

[kjk]

verified happens on master
probably same as #4064

[caribet42]

there is a change in behaviour between released version v3.5.2 and pre-release v3.6.16007.
Unfortunately it is wrong.
Specifically it addressed the matter of the fade mask, but the mask is inverted.
The capture from Adobe (above) shows the correct view, with a mask reveal at the bottom of the page and clear area (showing text) at the top. I have some other files where the mask reveals L-to-R and again the reveal is inverted in 3.6.16007

Attached screenshot of same file referred to above, but captured in 3.6.16007

[kjk]

the best thing to do is to report this to mupdf developers: https://bugs.ghostscript.com/

[GitHubRulesOK]

for convenience this should be single page with similar construct ?

Page2mupdf.pdf