Go to https://incubator.wikimedia.org/wiki/Wp/nys/Yira_djinang
Click on 'Edit source'
Make edit (e.g. insert new line 'test')
Click on 'Show preview'
**What happens?**:
[[Category:musician]] is autocorrected to [[Category:Musician]]
[[Category:Musician]] is not a current category, so under 'Parser profiling data:' it shows Musician in red
If you now press 'Publish changes' the page will be updated with the incorrect category
There was no warning about this change being made and the only clue that this happens is the red text if a new category is being created.
The red text is unlikely to be seen anyway as it appears right at the bottom of the wikipedia page, which is probably off the browser screen.
**What should have happened instead?**:
No change should have been made.
Clearly this could be a major problem if I'd have been going through multiple pages making edits and being unaware that I was introducing random errors in the category entries
**Software version** (skip for WMF-hosted wikis like Wikipedia):
**Other information** (browser name/version, screenshots, etc.):
Using a MacBook Pro Mojave 10.14.6 with either Safari 14.1.2 or Firefox 109.0.1
N.B. Firefox Preferences -> General -> Language -> Check your spelling as you type, is unchecked