Further comment on SPARQL 1.1 Test Cases

I am working towards getting dotNetRDF back to as close to 100% compliance
with the current state of the SPARQL 1.1 Query and Update specifications as
possible and have run into one test case which is confusing to me because it
seems as odd with SPARQL 1.0 behavior.

This is syntax-update-53.ru:

PREFIX : <http://www.example.org/>
INSERT DATA { 
              GRAPH<g1> { _:b1 :p :o }
              GRAPH<g2> { _:b1 :p :o }
            }
Currently my implementation rejects this on the grounds that the same blank
node is reused in different graph patterns.  It was my understanding that
the 1.0 specification forbade this and there are in fact a selection of 1.0
tests that specifically check that a parser rejects such queries.
So I assume one of three things must be true:
1 - This restriction has been removed in SPARQL 1.1 (if so where does the
spec state this?)
2 ­ The restriction does not apply to updates
3 - The test case is incorrect
I would appreciate some feedback on this specific test case but also that
the working group would please make sure the test suite is all up to date
and accurate (sorry to complain yet about this yet again but it really makes
it hard to check an implementation if you have to check for each failing
test whether the test case is actually correct)
Rob