If you automatically incite a cite use a url and the document contains a date which only specifies a month (I think) a bad reference is produced.
See for example this reference: https://en.wikipedia.org/w/index.php?title=Eliot_Freidson&oldid=1027001500#cite_note-:1-5
Reproducible bug
- Create a reference to the above url by copying and pasting the url