It was reported a few weeks ago on some other sites, but I don't remember seeing it here.
"Today, it looks like Google has begun an experiment on its search engine results page when users search from Chrome on mobile devices. Rather than show results in a lineup, separated by gray lines, Google is playing with a layout that puts each result on its own card, underscored by a line colored to match one of Google's four primary brand colors - blue, green, yellow, and red."
I've had the same thing for a couple weeks.