Aug 20 2015
It can be closed; it doesn't seem to be happening any longer. Thanks.
Apr 16 2015
From a user's point of view, I think the best thing VE could do for articles with DEFAULTSORT not set is to put the text of the article title in the default sort field so it's available for editing, but if the user makes no changes to it, do not save it. Perhaps a greyed-out look could be used to indicate that the text is unchanged and won't be saved. This gives maximum convenience with minimum need for the user to comprehend what's going on, and does not constitute a dirty diff.
Apr 6 2015
Jan 14 2015
It doesn't seem to have been mentioned above that this bug can cause the loss of a citation, which might affect the severity or priority. If you have a ref inside a group note (e.g. inside a tag) and delete all other copies of the ref, including the base copy, VE is unable to transfer the base text to the copy of the ref in the tag, so the citation is lost.