I use iCloud Drive for Books.
Consistently, highlights to PDFs in the Books app made on my iPad appear a totally different shade of their original color when viewed on my Mac.
For example, if I highlight text in blue or yellow on my iPad, when I view the highlights on my Mac, they appear a grey-blue or dulled yellow shade that is VERY distinct from the original.
Overall the color profiles between the two devices match. The same photo, website, etc. appears more or less the same when viewed on each device.
Consistently, highlights to PDFs in the Books app made on my iPad appear a totally different shade of their original color when viewed on my Mac.
For example, if I highlight text in blue or yellow on my iPad, when I view the highlights on my Mac, they appear a grey-blue or dulled yellow shade that is VERY distinct from the original.
Overall the color profiles between the two devices match. The same photo, website, etc. appears more or less the same when viewed on each device.