I have reported this issue to AngularJs team: angular/angular.js#14548

Basically their are right in their assumption that using zone.js should not change setTimeout. Imagine this situation when using zone.js.

var deferredTracker = {}

var timerId1 = setTimeout(function() {});
var timerId2 = setTimeout(function() {});

deferredTracker[timerId1] = new Promise(....);
defferedTracker[timerId2] = new Promise(....);

The result of defferedTracker is:

{"[object Object]": promiseInstance}

This is the way angular1 tracks timeouts and interval. Using zone.js allows to cancel only the last timeout or interval.

To fix this issue I would suggest for ZoneTask to have toString method which for setTimeout and setInterval should look like this:

toString: function() {
  return this.data.handleId;
} 

Without fixing this, using zone.js in angular1 application is just not possible.

Thank you