http://www.w3.org/TR/sparql11-query/#propertypaths defines "+" to signify "A path that connects the subject and object of the path by one or more matches..." I have found that in Bigdata revision 7202 on the BIGDATA_RELEASE_1_2_0 branch, this operator seems to be ignored. I attached a file containing a class hierarchy (top to bottom) A < B < C < D < E.
For this query:
I get B, as expected. Replacing the predicate with rdfs:subClassOf*, I get A, B, C, D, E, as expected. Replacing the predicate with rdfs:subClassOf?, I get A, B, as expected. However, replacing the predicate with rdfs:subClassOf+, I get only B, instead of my expectation of B, C, D, E.
I attached the dataset.