Go to the places tab and highlight the place name that is a date. Look at ‘Edit Place’ (column to the left of the screen), then to the section labeled ‘Place Items’, then ‘Events’. Here you should see a number, click on the arrow to open that field, The facts where that “place” is used should slide in. Use the pencil button (Edit Item) to jump to the Edit Person screen where that date is used and correct it. When back to the Places tab, the Show Unused Places is in the Ellipsis shaped Option menu (3-dots) in the bar above the places.