https://en.wikipedia.org/w/index.php?title=N_postcode_area&diff=950493632&oldid=926961243
The bot stepped in and escaped closing brackets on these templates, such as
*{{cite postcode project|N1|archive=https://web.archive.org/web/20120925193628/http://www.museumoflondon.org.uk/postcodes/places/N1.html}}
to
*{{cite postcode project|N1|archive=https://web.archive.org/web/20120925193628/http://www.museumoflondon.org.uk/postcodes/places/N1.html%7D%7D
which naturally broke them.