Here are two fiddles using customBreaks:
Fiddle using numbers on axis (customBreak works): https://jsfiddle.net/api/post/library/pure/
Fiddle using Dates on axis (customBreak does not work): https://jsfiddle.net/hLycfrqa/
The X-axis on the numeric axis continues to display the labels after the customBreak occurs. You can see it goes from 200 before the break to 1600 after the break.
The X-axis on the Date axis does not continue to display the labels after the customBreak. You can see 2002 before the break but no labels show after the break.
It seems no more axis labels will show after the first customBreak when using a Date on the axis. Seems like a bug to me.