Folder redirection: Local documents lost after enabling

Hello,

after enabling the folder redirection for one user, I experienced a data loss: All local documents were overwritten with the documents on the mapped server folder.

We managed to get the data back, but I'm not entirely sure why this problem exists. 

Before this, we enabled it for several other users, without having issues at all.

So, how can it happen that the online folder overwrites my local folder after enabling the folder redirection?

My guess is the setting "Move the contents of Documents to the new location", is this possible?

Thanks in advance and best regards.