Why is the front page trying to print?

[ErikGrim]

Going to the front page in Safari 11.0.3 one time it brought up the print dialog. Didn’t think much about it, I probably bumped something. Then later I access it again I get this:

JS error? Malicious ad?

 

[sman789]

Strange, I tried with Safari and Firefox (both logged in and not) and haven't seen that.

 

[AngerDanger]

Could it be… the ghost of print media?

 

[ErikGrim]

Strange, I tried with Safari and Firefox (both logged in and not) and haven't seen that.

It has only happened twice, so I’m suspecting a rogue script from an ad that somehow circumvents uBlock?