Hi Constance, I am Paulo and I'd like to help.
Where are you seeing the history still appearing? Did you exclude some websites to be cleared?
In the meantime, try clearing their site data and see if that helps. To do this, go to Edge Settings > Cookies and site permissions > Manage and delete cookies and site data > See all cookies and site data. Search the website then click the bin icon to remove and check if the issue is fixed. You may also click on Remove all if you intend to clear them all.