Animation Events not triggered in nested state graphs

See breadcrump:

|> State Machine: Movement & Attacking

|--> State Casting

|---> Starts State Unit: Fireball

|-----> Begins in state Init

|----------> Sets Animator-Integer

Now the animation starts, but the Animation Event "BeginSpell" is not triggered. Placing the listener into the state "Casting" will trigger the event correctly.

Bolt Version 1.2.3, Windows 10, Unity 2017.3

A workaround is to call the Animation Events via Custom Triggers, I put this into an "always-on"-state in the state machine: