I also tried the app on a Xiaomi and a Real phone, but they also had the same problem.
So I installed BlueStacks (an android emulator) on my PC.
You can find full instructions on the program's site: https://www.bluestacks.com/apps/lifestyle/mi-home-on-pc.html
I found a compromising solution. I installed the app (Mi Smart Home) on the PC with an android emulator, and worked perfect. Now I create the scenes on the PC and I manage them on my phone. It seems that the problem has to do with my phone (Samsung A52S).
I try to add a first scene in mi smart home app without success. I have add my devices. I set "if" and "then" condition but the app falls in a loop and starts over from "if" condition again! What's wrong with it? (I admit that I am new at home automation)