Datetime custom fields do not render the same way as system datetime fields

I'm using some date time custom fields in some projects. I have noticed that the custom fields do not follow the same rendering as the date time system fields.

For example, one of my custom fields captures the date and time of a workflow transition. The value of custom field is the same as Updated date time system field. Although values are the same the two date time fields have different rendering in view issue screen. More details in datetime_1.png.

The second inconsistency appears in issue navigator. In issue navigator the date time system field has only the date value but the date time custom field has both date time values. More details in datetime_2.png.