Same. I'm using a Surface Duo 2 and I saw a 1 star review for a Z Flip with a startup crash. So I think it's an issue with nonstandard screen ratios/resolutions.
I made a post on it in the app's community. May want to post there so the developer knows.
I'm slowly trying to build up my collection. While I like the benefits of cast iron, I know I'll slip up and not be able to maintain one. Then enameled cast iron swoops in with bright colors to the rescue.