.has step filters out vertices, that should not be filtered out (maybe BUG in indexing?)

[Kukant]

Lets go straight to the problem.
Firstly, I run this query:

g.V().has('name', 'Risk Services').
out('child').has('name', 'Risk Data Solutions').
out('child').has('name', 'PROVISIONING.BI').
out('child').has('name', 'S00000759').
out('child').has('name', 'O00031991').
out('child').//has('name', 'E00003982').
values('name')

Here is the result:

==>E00025282
==>E00057102
==>E00078153
==>E00073290
==>E00001772
==>E00003982

Now, lets uncomment this filter //has('name', 'E00003982'). and try again:

gremlin> g.V().has('name', 'Risk Services').
......1> out('child').has('name', 'Risk Data Solutions').
......2> out('child').has('name', 'PROVISIONING.BI').
......3> out('child').has('name', 'S00000759').
......4> out('child').has('name', 'O00031991').
......5> out('child').has('name', 'E00003982').
......6> values('name')
gremlin>

No results returned, even though one vertex matches this filter. How is that possible? I indexed the 'name' property. Is it possible there is a bug in the index? What info should I provide for debugging?