I had noticed from time to time in the past when I've been using Google Search that the underline on hyperlinks didn't always appear.
I put it down to different browsers & settings.
It turns out that Google had been testing whether the hyperlink being underlined or not made any difference or if people knew instinctively that text in blue is a hyperlink. Today it seems that the latter is true, Google have started to remove the underline from hyperlinks on Google search. Go look for yourself. A subtle, hardly perceivable difference.
As well as removing the underline, which appears to be part of the new look search for mobile devices, Google has released a number of updates and enhancements, you can read about those in this blog post Fifteen years on - and we are just getting started by Amit Singhal SVP Google Search