Google is now showing three local service ads listings in both the mobile and desktop interface. Previously, Google has shown two local service ads listings, but as Len pointed out on Twitter, Google is now showing three. The desktop interface has had three for some time, but mobile generally has shown only two listings.
I can personally replicate this, as can many others. Here is what I see on desktop and mobile Google Search:
Now, we have seen 3 before, but generally, it has been two local service ads, not three.
Forum discussion at Twitter.