Sorting by search param date doesn't work on DocumentReferences

[Jasopaum]

Description

A query where sorting is done by date on DocumentReference returns an empty bundle even if some DocumentReferences should be returned. Maybe it's in part due to the fact that the fields corresponding to the date param are empty?

Because of this, we can't dort documents by date in cohortInfo.tsx.

Reproduction

1. Try this query /DocumentReference?_sort=-date

Resolution

1. Try to see if this comes from hapi or not
2. ...