Here is the stack trace. I will try to narrow it down further.
java.lang.ClassCastException: clojure.lang.PersistentList cannot be cast to clojure.lang.IPersistentSet
at clojure.core$disj.invoke (core.clj:1420)
clojure.core.logic.ConstraintStore/fn (logic.clj:339)
clojure.lang.ArrayChunk.reduce (ArrayChunk.java:58)
clojure.core.protocols/fn (protocols.clj:94)
clojure.core.protocols$fn_5854$G5849_5863.invoke (protocols.clj:19)
clojure.core.protocols$seq_reduce.invoke (protocols.clj:31)
clojure.core.protocols/fn (protocols.clj:60)
clojure.core.protocols$fn_5828$G5823_5841.invoke (protocols.clj:13)
clojure.core$reduce.invoke (core.clj:6030)
clojure.core.logic.ConstraintStore.remc (logic.clj:338)
clojure.core.logic$remcg$fn__3272.invoke (logic.clj:2374)
clojure.core.logic$BANG$reify_3422.invoke (logic.clj:2719)
clojure.core.logic$composeg$fn__2569.invoke (logic.clj:1141)
clojure.core.logic$composeg$fn__2569.invoke (logic.clj:1142)
clojure.core.logic$run_constraint$fn__3285.invoke (logic.clj:2397)
clojure.core.logic$fix_constraints.invoke (logic.clj:2424)
clojure.core.logic$run_constraints$fn__3290.invoke (logic.clj:2434)
clojure.core.logic.Substitutions.bind (logic.clj:612)
clojure.core.logic$run_constraints_STAR_$fn__3296.invoke (logic.clj:2444)
clojure.core.logic.Substitutions.bind (logic.clj:612)
clojure.core.logic$run_constraints_STAR_$fn__3296.invoke (logic.clj:2446)
clojure.core.logic$EQEQ$fn__2647.invoke (logic.clj:1255)
clojure.core.logic.Substitutions.bind (logic.clj:612)
clojure.core.logic$rembero$fn_3465$_inc3466$fn3475$fn3476$_inc3477$fn3478$_inc_3479.invoke (logic.clj:2790)
clojure.core.logic$eval2628$fn_2633$_inc_2634.invoke (logic.clj:1223)
clojure.core.logic$eval2628$fn_2633$_inc_2634.invoke (logic.clj:1223)
clojure.core.logic$eval2628$fn_2637$_inc_2638.invoke (logic.clj:1220)
clojure.core.logic$eval2628$fn_2633$_inc_2634.invoke (logic.clj:1223)
clojure.core.logic$eval2628$fn_2633$_inc_2634.invoke (logic.clj:1223)
clojure.core.logic$eval2628$fn_2633$_inc_2634.invoke (logic.clj:1223)
clojure.core.logic$eval2628$fn_2637$_inc_2638.invoke (logic.clj:1220)
clojure.core.logic$eval2628$fn_2633$_inc_2634.invoke (logic.clj:1223)
clojure.core.logic$eval2628$fn_2637$_inc_2638.invoke (logic.clj:1220)
clojure.core.logic$eval2628$fn_2629$fn_2630.invoke (logic.clj:1225)
clojure.lang.LazySeq.sval (LazySeq.java:42)
clojure.lang.LazySeq.seq (LazySeq.java:67)
clojure.lang.RT.seq (RT.java:473)
clojure.core$seq.invoke (core.clj:133)
clojure.core$take$fn__4112.invoke (core.clj:2501)
clojure.lang.LazySeq.sval (LazySeq.java:42)
clojure.lang.LazySeq.seq (LazySeq.java:60)
clojure.lang.LazySeq.first (LazySeq.java:82)
clojure.lang.RT.first (RT.java:566)
clojure.core$first.invoke (core.clj:55)
clojure.pprint$pprint_reader_macro.invoke (dispatch.clj:50)
clojure.pprint$pprint_list.invoke (dispatch.clj:77)
clojure.lang.MultiFn.invoke (MultiFn.java:163)
clojure.pprint$write_out.invoke (pprint_base.clj:194)
clojure.pprint$pprint_vector$fn__7949.invoke (dispatch.clj:83)
clojure.pprint$pprint_vector.invoke (dispatch.clj:82)
clojure.lang.MultiFn.invoke (MultiFn.java:163)
clojure.pprint$write_out.invoke (pprint_base.clj:194)
clojure.pprint$pprint$fn__7359.invoke (pprint_base.clj:250)
clojure.pprint$pprint.invoke (pprint_base.clj:248)
clojure.pprint$pprint.invoke (pprint_base.clj:245)
logicpuzzles.corefail$show.invoke (corefail.clj:9)
logicpuzzles.corefail$eval3796.invoke (corefail.clj:153)
clojure.lang.Compiler.eval (Compiler.java:6511)
clojure.lang.Compiler.load (Compiler.java:6952)
user$eval971.invoke (NO_SOURCE_FILE:1)
clojure.lang.Compiler.eval (Compiler.java:6511)
clojure.lang.Compiler.eval (Compiler.java:6477)
clojure.core$eval.invoke (core.clj:2797)
clojure.main$repl$read_eval_print__6405.invoke (main.clj:245)
clojure.main$repl$fn__6410.invoke (main.clj:266)
clojure.main$repl.doInvoke (main.clj:266)
clojure.lang.RestFn.invoke (RestFn.java:1096)
clojure.tools.nrepl.middleware.interruptible_eval$evaluate$fn__544.invoke (interruptible_eval.clj:56)
clojure.lang.AFn.applyToHelper (AFn.java:159)
clojure.lang.AFn.applyTo (AFn.java:151)
clojure.core$apply.invoke (core.clj:601)
clojure.core$with_bindings_STAR_.doInvoke (core.clj:1771)
clojure.lang.RestFn.invoke (RestFn.java:425)
clojure.tools.nrepl.middleware.interruptible_eval$evaluate.invoke (interruptible_eval.clj:41)
clojure.tools.nrepl.middleware.interruptible_eval$interruptible_eval$fn_585$fn_587.invoke (interruptible_eval.clj:171)
clojure.core$comp$fn__4034.invoke (core.clj:2278)
clojure.tools.nrepl.middleware.interruptible_eval$run_next$fn__578.invoke (interruptible_eval.clj:138)
clojure.lang.AFn.run (AFn.java:24)
java.util.concurrent.ThreadPoolExecutor.runWorker (ThreadPoolExecutor.java:1145)
java.util.concurrent.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:615)
java.lang.Thread.run (Thread.java:722)
There's far too much context here. Do you have a minimal case? Thanks much!