Got strange bug. I've done ew vids and photos over the weekend. Videos were quite big (1.3Gb; 850Mb; 450Mb). Then I wanted to upload all to OneDrive. All the photos passed through, but videos took extremely long time, so I ended the app.
Then, I normally re-rendered on my PC and uploaded via IE.
Now, even after I deleted all those photos and videos from my phone's photo hub, so they are not present on the phone any longer, I have significant decrease of phone memoery. There is ~4Gb less space than what I had before the videos and photos were taken.
Now, when looking into phone memory, it is OneDrive, taking 4,27Gb of the space. Detailed overview after pressing the OneDrive app in the list:
Total: 4,27 GB
Installation: 9,70 MB
Data: 4,27GB
Another thing is, the system size is now showing as 6,77GB, but it is quite clear, that it contains also those about 4,2GB, that is taken by OneDrive.
I don't know if the file upload got stucked somehow? Why the hell such huge increase in space occupied by the System?