Print does not show errors of parent nodes in workflow mode

Let us have this program:

a = 2 / 0
b = a
print(b)

When we print model.value we do not see the failed node a (due to a division by zero occurring at run time). We only see an n.c. in the output and no error message. This makes the impression that with b everything is OK and it is matter of time until we get the result. But there will be never any result. In such case something else has to be displayed and the cause referring to all failed evaluations.

The behavior is different in locally deferred mode and in immediate evaluation mode where print(b) catches and prints the error in a.