Instagram on Android - Wide Angle Distortion

I have recently noticed that Instagram uses the top portion of my phone's rectangular image sensor, instead of cropping a square from the exact centre. This seems an odd choice, considering that on wide lenses (which most phones have), the edges exhibit varying degrees of distortion.

My Google searches have yielded no results about this unorthodox cropping behaviour. Perhaps I'm using the wrong keywords.

Have any of you noticed this on your phones? Does it bother you?