Why doesn't AirMail3 save settings?

Question

macOS

Hello everyone
Problem
I installed AirMail 3 on my iMac. I really like the client - it works fast, synchronization with the server is super fast, support for various goodies and Imap boxes (one of the main reasons why I installed this client). It so happened that over 15 years of work in different directions, 9 boxes were formed and they all need to be checked.
There are 2 fly in the ointment:
1. A folder (label) with the name AirMail and 4 subfolders appeared in all boxes. I tried to delete it, turn it off in the settings, everything appears exactly after turning it on.
2. It seems that the settings are exported to iCloud and in fact everything can be restored on a new device in 2 clicks, but the settings are crooked and half have to be adjusted.
In fact, if it weren’t for these 2 spoons, this client would have bought both for a poppy and for an iPhone.
I searched on the Internet, no one raised such a question. There is a suspicion that this is due to the fact that the version is broken, you don’t want to pay to check the client. But! I downloaded different broken versions from different sources, set it up and everything repeats.
Question? Is it my karma, crooked hands or a crooked version? =)
Thank you for keeping silent, instead of stupid answers.
UPD: Found a great alternative to Spark. Everything is super, both clients are free (poppy and phone) and very usable, IMAP support and a lot of boxes. But often it gives a communication error with the server both on the computer and on the phone. Can someone tell me a solution, along the way, or is it a bug of the program itself? Share your experience dear Toasters