Busy Cursor Rapid Oscillation While Web Browsing

I have noticed lately that, occasionally, while I am reading an article on any number of various websites, my cursor will begin to rapidly oscillate between the typical arrow and the blue ring busy cursor for maybe a second at most in duration. I haven't noticed the webpages hanging in any way or refreshing; that is to say there are none of the blue rotating circles in any of the open webpage process tabs that would indicate any new webpage activity specific to that webpage loading into the page's process. I tend to notice this happening when I am reading a page with no additional interaction--I am typically not even touching the mouse when I see it occur.Basically, I am wondering what different things might be causing the momentary activity. I am using Google Chrome for my browser and have nineteen extensions installed, so, I was thinking possibly I am seeing an extension occasionally updating or possibly checking for updates. That is just an uneducated speculation out of the blue. It also may be that this has always happened since loading Chrome, that for some arbitrary reason I just began to focus on it, and, having now fixated upon it, it stands out.