What is the Impact of Google’s green outlined ‘Ad’ label replacing solid green version on search results?

At the moment, not even Google can answer that question, I know that because I spoke to them last week. This is just one of many tests that Google conducts to try and make the Ad experience better. This is more of an aesthetic look that they are testing out and they will only decide to keep it if the data shows them a better interaction/conversion rate for Google. The integration of Ads in Organic results is something that Google wants to implement so whilst the consumer do know that they are Ads but at the same time they should not stand out too much. Down the line we will know how this worked out for Google.