Input:default-graph-uri not being applied

Virtuoso Universal Server
1

I’d like to post this here to before posting a bug to github.

This query correctly returns the content of the Named Graph specified by input:default-graph-uri:

define input:default-graph-uri <https://medium.com/@sdmonroe/vios-dev-content-monetization-8c2a05f4a987> 
select ?s1 as ?c1 count (*) as ?c2 where { 
select distinct ?s1 ?g  {
  ?s1 a <https://medium.com/@sdmonroe/NewsArticle> . 
  quad map virtrdf:DefaultQuadMap { 
    graph ?g {  ?s1 ?s1textp ?o1 . ?o1 bif:contains  '"vios"'  . } 
  }  
} 
} 
group by ?s1 order by desc 2 limit 15  offset 0

Here is the same query with only the Named Graph changed. It also produces the correct result:

define input:default-graph-uri <https://medium.com/@sdmonroe/vios-reference-implementation-3153a3d589cf>     
select ?s1 as ?c1 count (*) as ?c2 where { 
select distinct ?s1 ?g  {
  ?s1 a <https://medium.com/@sdmonroe/NewsArticle> . 
  quad map virtrdf:DefaultQuadMap { 
    graph ?g {  ?s1 ?s1textp ?o1 . ?o1 bif:contains  '"vios"'  . } 
  }  
} 
} 
group by ?s1 order by desc 2 limit 15  offset 0

When I remove the class constraint, items enter the result set that do not belong to the specified Named Graph:

define input:default-graph-uri <https://medium.com/@sdmonroe/vios-dev-content-monetization-8c2a05f4a987>     
select ?s1 as ?c1 count (*) as ?c2 where { 
select distinct ?s1 ?g  { 
  quad map virtrdf:DefaultQuadMap { 
    graph ?g {  ?s1 ?s1textp ?o1 . ?o1 bif:contains  '"vios"'  . }
  }  
} 
} 
group by ?s1 order by desc 2 limit 15  offset 0

Here is the same query with only the Named Graph changed. It returns the same list as the one above:

define input:default-graph-uri <https://medium.com/@sdmonroe/vios-reference-implementation-3153a3d589cf>     
select ?s1 as ?c1 count (*) as ?c2 where { 
select distinct ?s1 ?g  { 
  quad map virtrdf:DefaultQuadMap { 
    graph ?g {  ?s1 ?s1textp ?o1 . ?o1 bif:contains  '"vios"'  . }
  }  
} 
} 
group by ?s1 order by desc 2 limit 15  offset 0