We always warn about the risks of installing a beta on the main working system. The betas are designed for him developer work, to test all the errors that a system or an application may have and give them a solution before we have it in our hands.
An example of this are the problems we encountered in the first macOS Catalina betas and the interaction with iCloud. Up to beta 3 iCloud developer has presented significant problems, creating an unstable and at times insecure system. This supposes a serious problem, which Apple has since fixed.
These problems have even reached the loss of files. These are very serious problems, faced by those who are too daring. In this case, by affecting the apple cloud, the problem is carried over to all devices that iCloud sync. That is, if such a file is deleted on the Mac, it is deleted in all open iCloud sessions, losing that information.
Finally Apple has fixed these problems in the macOS Catalina beta 4. In the update notes, it did not initially indicate which problems have been fixed, but Apple published it somewhat later in the update description. In these notes it indicates that various iCloud bugs have been fixed. Problems caused were when sharing iWork documents, downloading documents from iCloud Drive, or creating empty folders in iCloud Drive.
Another problem that has been repeated is the document sync on the desktop or in the documents folder. It may not sync up to date correctly. After beta 4, this error should be fixed deactivating and re-activating iCloud Drive. Since we do not know its behavior, it is just that, a beta, we recommend using a test ID and not the usual ID. In this way we avoid major problems.