Last modified: 2013-09-25 01:29:55 UTC
If you select some text whose first word is bold, and attempt to make it all bold, it will look as though it has succeeded, but actually too many ' characters have been added, so it will appear as bold, italic and single-quoted, when saved! Note: my selected text also included an internal link - that might have been relevant.
This /might/ be fixed by bug 42803, which currently has a patch awaiting review.
Pretty sure that this is the same as bug 42803; merging. *** This bug has been marked as a duplicate of bug 42803 ***