The problem with your bug messaging
You provide the wrong error code again for many users here: https://xtools.wmflabs.org/articleinfo/fi.wikipedia.org/Syyrian_sis%C3%A4llissota#bugs
Why?
- "The ISBN might lack dashes between the digits, or it might contain spaces between the digits, but it still provides the link." https://en.wikipedia.org/wiki/Help:ISBN
- "Spaces and hyphens in the ISBN do not matter." https://en.wikipedia.org/wiki/Wikipedia:ISBN
- "The use of hyphens or spaces has no lexical significance and is purely to enhance readability" ISBN manual, 2017, p. 11 https://www.kb.se/download/18.71dda82e160c04f1cc412bc/1531827912246/ISBN%20International%20Users%20Manual%20-%207th%20edition.pdf
What should have happened instead?: You should not report bugs when there are none.