Strange OneDrive behavior

Hello everyone, in different customer installations we notice a strange behavior of OneDrive.

1. (MAC OneDrive) - Files, no Office formats but jpg. or pdf. do not open directly (but a preview is displayed) - an error message says that there is no authorization - the second click opens the file
2. (Windows and MAC) After editing Office files and closing the file and opening it again, the file is opened in read-only mode - saving is then only possible in a new file
3. (Windows) After editing Office files, the file is checked out - without this being set or initiated by the user

Does somebody have a idea why or a solution?

Thx much in regards

Nik