Agile Wallboard Gadget is refreshing itself every minute even with the Refresh Interval set to Never

Steps to reproduce:

1. install JIRA 5.x or above
2. add the Agile Wallboard Gadget into the Dashboard. Ensure that the Refresh Interval is set to Never as shown in screenshot AgileWallboardGadget.png
   Expectation, it will never refresh unless the user refresh the browser or the gadget manually.
3. (BUG) the behaviour observed is that, the gadget seems to be flicking and in the Developer Tool's Network tab we can see there are request thrown within a minute different. Refer to screenshot NetworkTab.png

This is tested in Incognito mode and browser without any extension installed.