There are a few other oddities with common words. It doesn’t recognize “checks”, for example - or “recognize”, spelt with a ‘Z’.
I thought it would, as it seems in some respects to be rather biased towards American English, which tends to favour the ‘Z’ spelling. I’m sure it’s at least optional, and not wrong.
It’s also marking: “biased” wrong! I suppose it wants “biassed”, which is definitely wrong! Sure enough, when I intentionally misspell it like that, it gets the all clear.
Shame the people who set up the dictionary didn’t have…well, a correct dictionary!