allOf and referenced schemas always returning true for the referenced type about json_schemer HOT 5 CLOSED

>> schemaWithRefs  = {
?>   "$id" => "NAME_HERE",
?>   "$schema" => "http://json-schema.org/draft-04/schema#",
?>   "type" => "object",
?>   "description" => "A Host entity has been created or changed",
?>   "required" => ["host"],
?>   "additionalProperties" => false,
?>   "properties" => {
?>     "host" => {
?>       "description" => "Host",
?>       "allOf" => [{"$ref" => "https://my-url-here.com/EDM.json#Host"}],
?>       "required" => ["attribute1"]
>>     }
>>   }
>> }
=> {"$id"=>"NAME_HERE", "$schema"=>"http://json-schema.org/draft-04/schema#", "type"=>"object", "description"=>"A Host entity has been created or changed", "required"=>["host"], "additionalProperties"=>false, "properties"=>{"host"=>{"description"=>"Host", "allOf"=>[{"$ref"=>"https://my-url-here.com/EDM.json#Host"}], "required"=>["attribute1"]}}}
>>
>> refSchema = {
?>   "$id" => "#Host",
?>   "properties" => { "attribute1" => { "type" => "string"  } }
>> }
=> {"$id"=>"#Host", "properties"=>{"attribute1"=>{"type"=>"string"}}}
>>
>> schema = JSONSchemer.schema(schemaWithRefs, ref_resolver: proc { refSchema })
=> #<JSONSchemer::Schema::Draft4:0x00007fe5b932fce8 @root={"$id"=>"NAME_HERE", "$schema"=>"http://json-schema.org/draft-04/schema#", "type"=>"object", "description"=>"A Host entity has been created or changed", "required"=>["host"], "additionalProperties"=>false, "properties"=>{"host"=>{"description"=>"Host", "allOf"=>[{"$ref"=>"https://my-url-here.com/EDM.json#Host"}], "required"=>["attribute1"]}}}, @format=true, @insert_property_defaults=false, @formats=nil, @keywords=nil, @ref_resolver=#<Proc:0x00007fe5b932fdd8@(irb):47>>
>>
>> schema.valid?({ 'host' => { "attribute1" => nil } })
=> false
>> schema.valid?({ 'host' => { "attribute1" => 'x' } })
=> true