Statechart Checks : (C1037) Compound transitions with nonorthogonal sources

(C1037) Compound transitions with nonorthogonal sources

There are compound transitions whose source set of states contains nonorthogonal (exclusive-or) states.
Error In:
Correctness
Example:
In the following figure, S1 and S2 are nonorthogonal states whose exiting transitions are contained in an illegal compound transition.
Erroneous Elements:
Components of the erroneous transitions