This is demonstrated in https://github.com/opencog/atomspace/tree/master/tests/query/unify-test.scm lines 197 ff The actual and the expected results don't match. My guess of where the bug is, is that its in the static analysis of `IdenticalLink`. Basically, `IdenticalLink` tries to do a static analysis, which, if its possible, avoid the need for a dynamic run of the query engine. But this static analysis is relatively minimal, kind-of dumb. And my guess is that it failed to notice that it's dealing with an unordered link. I think that's where the bug is. But it could be somewhere else ...