Sorting functionality does not work on Custom entities

Problem/Motivation

I am trying to sort a custom entity by date to be displayed on an Overview page. The sort does not work as expected.

Steps to reproduce

1. Create a custom entity type.
2. Add a Date field to the Bundle.
3. Create dummy entities with date value.
4. Sort the Custom entity based on date.

The sort does not work on DateTime, Title, Timestamp and/or Number.