Saving Annotations not working properly

Hi, I just want to annotate PDFs that are stored in my owncloud. When I open a PDF file via the owncloud app using Adobe Reader and then select the annotation function, Adobe Reader saves a copy of the file in the download folder. My annotations are therefore not saved in the original file, but in the copy. This behavior is completely stupid. If I want a copy, I can download it myself. But I don't want a collection of duplicates in my download folder, which I then have to rename manually, delete the old file in the cloud and then upload the annotated copy with the old name back to the cloud. Why can't I simply save my comments directly in the original, as I can in Adobe Reader for Windows? Is this a bug or a feature of yours? Is there any way to circumvent this behavior?