William Michael Kanar

I can confirm this exists in 1.19 on mobile with 1.19.1.01 server software. I resolved it with workaround 3.

I've noticed this in 1.18.32

One or both of you likely lack a stable internet connection. You may try moving closer to the router, or using an Ethernet cable.

If you live far away from each other, then your ISPs might not provide a good route. If that is the case, then there's not much you can do.

When I tried to replicate this bug for myself on Windows 10, I had trouble getting the stairs to all be corner stairs. With trial and error, I got it to work as intended. Try placing them in a spiral motion. 

Are you sure you are in the beta program? The title screen should be black and white with big words saying beta.