Theme colours changing with Zoom

mjthoraval

The colours of the PDF file change with the Zoom level when using the Dark theme (same also with any them other than Original):
https://s3.amazonaws.com/zotero.org/images/forums/u265723/nkvshupslbenidjuw7fo.png

https://s3.amazonaws.com/zotero.org/images/forums/u265723/duo47od801yunxvnbbw1.png

The grey colours appear around "Fit to Page Width".

I can even get both colours at the same time on different pages:
https://s3.amazonaws.com/zotero.org/images/forums/u265723/qthe7qvnqi9i95zbex0y.png

https://s3.amazonaws.com/zotero.org/images/forums/u265723/y8d3utydo8zkg11f7im1.png

Tested on this article:
https://link.springer.com/article/10.1007/BF01591664

Zotero 7.1-beta.12+8e0852799 (64-bit)
Windows 10

[I have sent the PDF file to support@zotero.org.]