The behavior described is a result of differing execution times between the client-side and the server-side. When using a "Reset Group" action, the server will not update the group's value; thus, if the group had any data in it at the start of a workflow, and the group's value is referenced later in the workflow, the server-side workflow execution will differ from the client-side workflow execution.

When using the "Reset Input" action, the action never updates the workflow's state server-side, so further references within the workflow to the input's value will get the value from before the reset.

The workaround here is to replace instances of "Reset Group" with "Display Data" and have the data to be displayed be the default data of the group.