iPhone 6/6 Plus: UITableView separator flickering and different thickness

I've got a UITableView with separator set to Single Line.

On iPhones <= 5s everything looks fine, but on 6 and 6 Plus (device as well as simulator) the separators have a different thickness. It's even worse as they're flickering while scrolling which looks pretty bad. I don't set the height manually, so I have no idea what's causing this.

As you can see, the first two lines are a little bit thicker than the next two. Now if I scroll, they change from thick to thin and back, so it looks like flickering...

The problem is that your app doesn't support native resolution for the iPhone 6 and iPhone 6 Plus. Therefore it gets scaled up which results in the flickering.

You can enable native resolution by adding iOS8 launch images. Then your app will run in the right resolution and this problem will be fixed.