Whether you click the clear icon in a field the change event is executed before the clearicontap event. This prevent the expected behavior.
According to this 2015 Sencha forum they detected the issue in order to find a solution but it is not solved.
Live Example: https://fiddle.sencha.com/#view/editor&fiddle/2s40
You can override the onClearIconTap
method on textfield and fire new custom event there.
Check the example on fiddle: https://fiddle.sencha.com/#view/editor&fiddle/2s4p