I was highlighting this document, then I left it open for a while and did something else and when I returned to continue highlighting, the color had miraculously changed on its own. As you can see in the image, the "magenta" looks almost lit it is itself highlighted, but if I right click the darker highlight, it also says magenta. It just changed half way through the document. I am new to Zotero, but I couldn't find any other posts talking about this so maybe its just a bug in my installation? I have not tried any other highlight colors, so I don't know which one is right or if there is a setting or something. I haven't don't anything in the program other than add documents to the collection and merge duplicates.

https://s3.amazonaws.com/zotero.org/images/forums/u16832240/oek9npyos9tm03cmysay.png