Report ID is 1230700118, I'm on a macbook neo and the latest version of Zotero. When I highlight across a citation in Zotero, it highlights the whole paragraph instead of just my selection as seen below (first photo is my selection, next is the result of highlighting)
https://s3.amazonaws.com/zotero.org/images/forums/u19905410/ixq8nizztxabq7dso1nh.png
https://s3.amazonaws.com/zotero.org/images/forums/u19905410/x6ha8m7ukbhhncacvvyv.png

I've never submitted a bug report so let me know if there is any missing information. Hovering over citations also doesn't show me the preview like it does in the regular mode, but I don't know if this is a bug or just a missing feature.

By the way, in spite of these minor inconvenience, I'm a big fan of the reading mode, it's much clearer to read PDFS this way for me. :)