I still encounter problems with resumed downloads often. Files had wrong sizes or were corrupt. Mostly it happens when network connections occur and transfer is aborted inproperly.
recently a transfer stopped just before it was finished. resuming lead to a much larger file
another file was at 700 of 900 Mb and I resumed. While uploading continued it showed 108Mb were finished of that file!! I checked the directory and file showed 1.2Gb now but should only be 900
I had uploaded a file partially and deleted it to start fresh. When I drap&dropped I was asked to overwrite or resume showing it still existed but it was gone. It seems that although directory has changed the upload function did ignore that or had a cached directory.