COB is injecting a disjointness which makes this apparent
The solution suggested by @cmungall is to create a more general relation in RO to be used by ENVO (and give the existing relation a more specific name). I can also make an issue in the RO repo for that. (update - see https://github.com/oborel/obo-relations/issues/636)
I'm looking into various incoherencies when merging OBO ontologies, as part of the Ubergraph build. Here is one unsatisfiable class:
exposure to mine drainage SubClassOf Nothing
The problems here are:
The solution suggested by @cmungall is to create a more general relation in RO to be used by ENVO (and give the existing relation a more specific name). I can also make an issue in the RO repo for that. (update - see https://github.com/oborel/obo-relations/issues/636)