How to reproduce:

Create a new Storage Pool and give it a name with a Space in it, e.g. "Test Pool"
Under "Apps", click "Settings" --> "Choose Pool" and use the newly created "Test Pool" as App pool.
If you install a custom app and are able to choose a data path, you now can see two version of the newly created Storage Pool. Once the original pool named "Test Pool" and once the pool that is created while switching the app poolt to the newly created storage pool. In this case, this second "Test Pool" is named "Test\ Pool":
This "backslash-Pool" is also visible e.g. by using FTP: