The android gmail app is horrible with this. They load a couple of your emails above ads so that the ads start on the second or third row.

And the re-ordering happens as your mails and the ads are loading! You might be about to tap your email, then the ads load in and you suddenly click on an ad. Or you want to tap the top row, but the app decides to put a different email above the ads and you end up tapping into the wrong mail because it was reordered just before the tap.