Normal
I have had 17 and 19 and they both do this after pumping gas. It has to do with where the vent is at for the fuel tank. When you fill it up and the pump clicks off don't fill it anymore and it won't be as bad. Weird thing is it does it worse with higher octane fuel. If I fill with 87 octane it won't do it unless I fill it to the top after pump clicks off. Hope this helps