Ran into this same issue. In addition to when clicking the Reset button on the Group Filter Widget and features not being re-rendered (though were still able to be seen within the Attribute Table), I was getting the same outcome with the Filter and Query Widget AND when filtering within the Attribute Table, then removing the filter.
Realized the issue wasn't with the data, rather, it was the Arcade expressions set with the pop-up that was causing the features to not be re-rendered. So IF you have Arcade expressions set, this may be one of the reasons the Reset button isn't working.