Visual editor sometimes inserts <nowiki>-</nowiki> instead of - into tables.
See an example at this diff. The user wanted to insert a hyphen into a table cell. Using | - would be valid wiki syntax, but instead it inserts |<nowiki>-</nowiki>.
When I try to reproduce it myself, I get | -, which is good, but I often see |<nowiki>-</nowiki> instead.