I tried using this example to set custom formats and after some frustration I made copy of fiddle example where each of support’s interval calculations result in an alert: http://jsfiddle.net/8e98Lej8/1/
While e.trigger is found to be set to Zoom none of the conditions is ever true when zooming.
Am I failing to get this or is the example no longer valid?
Because of multiple X / Y axis support, all axis parameters in events like rangeChanging / rangeChanged have been changed to array from object (Since v1.8.5), refer this release-post for more info. Changing e.axisX to e.axisX should work fine in your case. Please check this updated jsfiddle.
We had missed out updating this jsfiddle. Thanks for bringing it to our notice, we have updated the jsfiddle accordingly.