I’ve seen two problematic editions on articles where the infobox’s templatedata contains format: block:
- https://fr.wikipedia.org/w/index.php?title=Windows_10&curid=8363380&diff=123774174&oldid=123747696
- https://fr.wikipedia.org/w/index.php?title=Microsoft_Windows&diff=prev&oldid=123760468
The diff is unreadable… I guess this is caused by the space on each line before the delimiting pipe?