When a canvas is created or an image is imported and the height is larger than the width then the layer preview, canvas rotation and transformation options become distorted. There seem to be no problems with a landscape orientation.

See the link below for a video demonstration:
https://youtu.be/kQaL0eIF0_g

Also towards the end of the video I was temporarily unable to select the toolbar along the top, I have encountered this a few times but have yet been able to reproduce.

Running on a Samsung S7+