Describe your context

dash                 1.3.1        
dash-core-components 1.2.1        
dash-html-components 1.0.1        
dash-renderer        1.1.0        
dash-table           4.3.0

 - OS: Linux (Debian 10)
 - Browser: Firefox
 - Version 60.9.0esr (64-bit)

Describe the bug

I have a callback who's input is the "n_intervals" attribute of a dcc.Interval component. If the callback function takes longer to return than the length of the interval driving it, then page layout is never changed by this callback. The updating of page layout silently fails. My current temporary fix is to make the intervals for these callbacks much larger than I would like, making the application sluggish.

Expected behavior

The page layout should be updated with the latest return value available, even if the callback has fired again and is awaiting a new return value.