In Google Ads, a broad match keyword of 3 words doesn't match a search with a 4th word inserted

In Google Ads I have a broad match keyword which is pcr testing employees

If I search with pcr testing employees then I get a match. Good.

If I search with pcr testing for employees then I don’t get a match. Inserting for breaks the match. Why is that? Seems to be the case for any word I insert.