Steps to replicate the issue (include links if applicable):

• Unclear, the issue has been observed in a specific edit, once.
• Link: https://pl.wikipedia.org/w/index.php?title=Twierdzenie_japo%C5%84skie&diff=prev&oldid=79648481

What happens?:
An unnecessary nowiki tag is inserted, separating the letters after the linked page’s name from the link. In this edit the nowiki tag is inserted changing "czworokąta" to "[[czworokąt]]<nowiki/>a".

What should have happened instead?:
The nowiki tag should not have been inserted. In the provided edit the correct output should be "[[czworokąt]]a".