if i looked into the code of org.basex.server.Query is see the object value "pos" which is from the java type int. In the basex version 6.7.1 this "pos" variable did not exists. Also in the new 7.0.1 version some caching mechanism seems to be implemented, which was not in the old version. I think, in these methods the problem could be raised.
Since Version 7.0 of BaseX, to avoid deadlocks and increased memory usage, iterative query results are completely sent to the client before the actual iterator is triggered; this is why the "pos" variable disappeared in the Query class.
Christian