A refresh Time of 0 means that the grid is not doing any automated refresh. If you want the grid to refresh itself, you need to set it up. This always results in a new retrieve (every x seconds).
Case 1:
The refresh mechanism you are describing (UI is refreshed because of a user interaction) does always only work for the user that executed the action.
Case 2:
Your application seems to use data from the cache instead of retrieving it from the database again. You could avoid this by using a microflow to open the Agent_NewEdit page. Within this microflow you can retrieve your object from the database and pass it to the page.