IABot left pipe characters in the title= parameter of a cite template, causing an "unnamed parameter" error. See https://en.wikipedia.org/w/index.php?title=1972_California_Angels_season&type=revision&diff=856999723&oldid=847963918 as an example. This happened on 29 August 2018, so it's possible this bug has been fixed.
The bot should escape pipe characters using the {{!}} template or |.