angular2-notifications: Failed to execute 'animate' on 'Element': 'null' is not a valid value for easing

Whenever a notification message pops up, console shows this error: EXCEPTION: TypeError: Failed to execute 'animate' on 'Element': 'null' is not a valid value for easing and the app stucks.

showProgressBar: true but there is no animation of progress, seem like a problem with the notification progress…

Any idea?