I was just going through a workout book when I noticed this odd light blue highlight over the "beans" in the second page. Lighter blue than any of the highlight colors. And when I ran my mouse over it, it showed a picture overlay of the previous page with the "beans" of that page highlighted in red! I've never seen this functionality before and have no idea what it is or what's causing it. Does anyone have any ideas?

For context, I'm using zotero 7, with zotmoov, and am annotating on a boox note air 3c. I also checked other parts of the workbook where there are duplicate graphs (as I thought it may be caused by this), but wasn't able to duplicate it anywhere else! I also checked it with my browser pdf reader and the overlay did not appear, so just zotero...

https://s3.amazonaws.com/zotero.org/images/forums/u13039982/d1yqbkeqtwmj712ffrx5.png