This HTML5 document contains 4 embedded RDF statements represented using HTML+Microdata notation.

The embedded RDF content will be recognized by any processor of HTML5 Microdata.

PrefixNamespace IRI
isaphttp://webisa.webdatacommons.org/prov/
n5github.
isahttp://webisa.webdatacommons.org/
rdfhttp://www.w3.org/1999/02/22-rdf-syntax-ns#
provhttp://www.w3.org/ns/prov#
xsdhhttp://www.w3.org/2001/XMLSchema#
Subject Item
isa:168992223
rdf:type
prov:Entity
prov:value
Without having gone through the code that creates the maps, etc., that are needed in your example, it does sound very much like the same sort of issue and could perhaps be the exact same thing.
prov:wasQuotedFrom
n5:com
Subject Item
isap:35713875
prov:wasDerivedFrom
isa:168992223