When your device cannot reach Airtable, a widget keeps showing the last value it retrieved rather than emptying itself. That is deliberate: an old number you can recognise is more useful than a blank tile.
It will pick up again on its own once you are back online and iOS schedules the next refresh. To hurry it, open the app.
Air Widgets never invents a number. If it cannot draw a widget, it says so rather than showing a plausible-looking value.