V2 calendar source does not allow an aggregate Grouping field as a Date Field

Defect/Issue Description:
A description of the bug


  • API Version: *** v2 ***
  • Release: *** ? ***
  • Release version: *** 15.1.6***
  • Platform: *** Salesforce ***

Migrating a Calendar from V1 to V2.
The Calendar has 2 sources, both are based on Aggregate models.
Both models / objects have both Date and Datetime fields, where the Datetime fields are formualic copies of a Date as a workaround for the V1 calendar.
One of the models Groups on the Date field, and aggregates (MAX) the datetime copy.
The design calls for reporting events by date, not by time, the V2 calendar is changed from “Start/end date and time” to “Single date” Date Field Type.
The new picklist for the Date Field property does not include the Date grouping.
If I try to add the Date field as an Aggregation, the generated SOQL becomes invalid, as the Grouping field is already included in the Select clause (as well as the Group By
Although the Grouping field is part of the Select clause, the skuid composer does not expose it in the Date Field picklist.
I can edit the page XML and add a startField=“datec” attribute to the <eventSource…> tag and get the expected events on the calendar.