The option to automatically recalculate answers is missing
The option won't be visible if you've modified the widget in a way that's not compatible with the recalculation function.
The option Update autocorrection with latest widget version is found in the overview page of a widget's results, when clicking the cogwheel under Answers. But not always.
Having student results recalculated this way has its limitations. Some modifications to a widget aren't compatible with this function, in which case the option won't be in the list.
The specifics of what you can and can't do with a widget in order to be able to use this function can be found here: