Two reasons why the weird crop is happening.
1st
This happens in small studios with a small budget or not enough production resources. That results in creative production being only about one or two formats that are used basically for everything. Vertical or horizontal because this fits almost every AdNetwork, it is time-saving and cost-saving and Facebook works with what it got.
But when you add a little more effort and create additional creative ratios you can drive outstanding results with your creative champion from all available placements.
2nd
This happens in studios that have enough resources to make all available creative formats but they make a mistake when creating a campaign and selecting a media crop for each placement or by using Advantage+ App Campaigns. Don’t get me wrong I love using Advantage+ App Campaigns as this simplified setup helps me lower cost per install and from time to time lower cost per action than a manual app install campaign setup. But you really don’t have control over which creative is used for each placement that you have in a „tailored setup“ manual app install campaign setup.
So what’s the hack that can help you to increase performance and squeeze in the maximum from your creative champion?