Issue is very sensitive and little tricky the observation(fix) i have made for this as follows,
When u called Activity B from Activity A the source activity(A) instance should be in stack(memory) to invoke "onActivityResult" callback.
The issue explained with reason below,
Observation: From Material design back and NavUtils.navigateUpFromSameTask - the description of navigateUpFromSameTask as follows
"Convenience method that is equivalent to calling navigateUpTo(sourceActivity, getParentActivityIntent (sourceActivity)). sourceActivity will be finished by this call"
remember sourceActivity (A) is removed from stack(memory) when used this method.
when there is no sourceActivity(A) no base instance(A) left to invoke "onActivityResult" callback.