URI() function doesn't convert blank nodes

[agazzarini]

sample_data.ttl

@prefix dm:   <http://learningsparql.com/ns/demo#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix d:    <http://learningsparql.com/ns/data#> .
@prefix xsd:  <http://www.w3.org/2001/XMLSchema#> .

d:id1 dm:location _:b1 .
d:id2 dm:location <http://dbpedia.org/resource/Montréal> .
d:id3 dm:amount 3 . 
d:id4 dm:amount "4"^^xsd:integer . 
d:id5 dm:amount 1.0e5 . 
d:id6 rdfs:label "5 bucks" . 
d:id7 dm:shipped true  . 

CONSTRUCT query

BASE <http://learningsparql.com/ns/demo#>

CONSTRUCT {?s ?p ?testURI.}
WHERE 
{
  ?s ?p ?o . 
  BIND (URI(?o) AS ?testURI)
}

SOLRDF

<http://learningsparql.com/ns/data#id1> <http://learningsparql.com/ns/demo#location> _:B6efa5836X3A14d70878f21X3AX2D7ff9 .
<http://learningsparql.com/ns/data#id6> <http://www.w3.org/2000/01/rdf-schema#label> <http://learningsparql.com/ns/5 bucks> .
<http://learningsparql.com/ns/data#id2> <http://learningsparql.com/ns/demo#location> <http://dbpedia.org/resource/Montréal> .

JENA MEM MODEL

<http://learningsparql.com/ns/data#id1> <http://learningsparql.com/ns/demo#location> <_:871810c45c183668b016fa55d5c7a00f> .
<http://learningsparql.com/ns/data#id6> <http://www.w3.org/2000/01/rdf-schema#label> <http://learningsparql.com/ns/5 bucks> .
<http://learningsparql.com/ns/data#id2> <http://learningsparql.com/ns/demo#location> <http://dbpedia.org/resource/Montréal> .

[agazzarini]

The same query with URI(ENCODE_FOR_URI(?o)) is working