Hi,
After looking into this issue further, it is actually a bug in our DL reasoning. Were your ontology an SL (RL, EL, QL) ontology, you wouldn’t be seeing this.
Thanks for the report! I’ve filed a bug internally, we’ll continue looking at it and report back here with any news or workarounds. As a temporary workaround for this, you could use a different predicate. For example:
INSERT {?s :myTempRdfsLabel ?o} WHERE {BIND(rdfs:label as ?p) . ?s ?p ?o}
This would let you query on your temp variable for the same results without having to rely specifically on rdfs:label.