Statechart Checks : (C2023) Compound transitions without a trigger

(C2023) Compound transitions without a trigger

There are compound transitions, none of whose segments contains a trigger part in their labels.
Error In:
Completeness
Example:
The following figure shows two compound transitions, where the second transition is in correct. The transition from S1 to S2 contains the trigger event E. The transition from S1 to S3 is labeled with an action A, but the trigger is missing.
Erroneous Elements:
Components of the erroneous transitions