I have a webmap with configured popup on a date field:
Here you see the popup in the webmap viewer:
Created an Operation View in Dashboard, and do use Feature Pop-Ups.
I do open the Operation View in a browser, and the popup gives me the time:
Open the operation view in Dashboard but it does not give me the time in the popup, just the date:
Is this a bug in the Dashboard desktop client?
At the time you posted this question, I do not believe it was fixed yet. It was eventually fixed, but it is now broken again.
It appears that Operations Dashboard for ArcGIS has not picked up on this new configuration, as it does not work anymore. I asked the question here if you would like to follow that discussion:Date/Time (with seconds) in OD?
As Adam pointed out, with 10.3 Operations Dashboard you should be able to see the time value in popups. Please give the latest version of the app a try (you can download from it here) and let me know you still run into the issue.