JetPack Stats show javascript error in click stats

We use the JetPack site stats on our site, http://lifering.org, and we recently noticed that this Javascript error regularly appears in our click list:

javascript:return%20false;

Over the last 30 days this appears about 6 times a day, out of roughly 30 clicks per day; but it’s the second or third most common click.

Nobody has reported any errors; but our users wouldn’t necessarily do so. I don’t have any problems with the site myself, I’ve never seen this, and I can’t find anyone else complaining about it – I Googled the error message. I found one post suggesting it may mean some of our users have browsers that don’t support Javascript.

Is this something we could correct? How do I find it to correct it? Any suggestions gratefully accepted.