Source link broken after Save Online if nice link is set

2.0.3 and latest 2.1-dev 3d70ec8.

To reproduce, first follow any steps to get to a situation where

a) You have a score online on MuseScore.com
b) You have the score locally, with a working link to the online version in Score Properties
c) The online version is set to have a nice link

For example, upload any score to MuseScore.com using the "Upload" link at the top of the web page, which will automatically set a nice link, then download the score from MuseScore.com and open it in MuseScore. File / Score Properties will confirm that the Source field contains a working link.

Then:

1. File / Save Online. Description, tags, etc. will be all filled in. Click OK with the checkbox to update the existing score selected.
2. File / Save Online again. This time, it doesn't work. Open Score Properties, and the link has changed to the "nice link," which apparently can't be parsed.

Expected result: either the numeric code version of the link is fetched when uploading the score, or the nice link is also parsed.