I've checked in Spotify client, on the site as well. I am a premium user, which means I'm paying for getting rid of ads, or at least that is what I thought.
How come I get this in my spotify client?

In the image above "köp" means "buy" for those who do not speak Swedish.
It is non-intrusive I give you that, but I'm a man of principles and you are sneaking in these ads and that is not something I want to pay for.
Sure, you can call it "Ebjudande" (offer) rather than an ad, but like they say, you can put lipstick on a pig to make it prettier, but it will still be a pig.
Some information:
OS: Windows 10
Client: 1.0.16.104.g3b776c9e