My German isn't the best so it is easier for me to try to articulate this in English.
We've already tested Space in Space. I've tested it myself. It can lead to infinite loops of data continuously being downloaded. For example, you have your main Space (A) and your sub-Space (B).
This example is just from the view point on one machine.
Both Spaces are fine. For some reason you decided to recover Space A. That's fine. B is inside of A. So when Space is recovered everything in it is "redownloaded" or copied from the backup folder on that local machine. However, B still exists as it's own Space for everyone else who is a member of the Space and also for the user who created B. So, when Space A is emptied for the recovery process, B no longer exists until A has finished recovery. Does not sound like a big deal when you look at if from the Space owner's computer.
Now, from the viewpoint of another machine. I (we) are members of B. We have nothing to do with A nor do we even know that it exists. But when A is recovered, B is removed (on that machine) until A is recovered, since it is a sub-folder. So, on our computers, everything in B is moved to the trash can because when A was recovered, B was removed on that machine and when TeamDrive scanned B it saw that everything was gone so it did what it normally does and moved everything to the trash can. This, of course, creates a lot of traffic and I think files are of course duplicated because the first set are moved into the trash and then the restore data is put back in the Space. So you end up with the same files in the trash as you have in the Space but the files in B may no longer have its old versions. I'm not exactly sure anymore as far as the versions go, it has been a while since I tested this.
This happened to me during testing. This was the first hurdle, we have not really gone beyond that because figuring out how to prevent that is a huge task in itself. We would like to, of course, implement the feature but we wouldn't like to make things more complicated for the user.