diff --git a/src/runtime/communication.rs b/src/runtime/communication.rs
index e11cc827faf76186312b82a4e31457fe929bbd03..d7cd77cba7c3d4b5180bcc38bf376c961add6e3f 100644
--- a/src/runtime/communication.rs
+++ b/src/runtime/communication.rs
@@ -26,6 +26,7 @@ struct BranchingProtoComponent {
 }
 #[derive(Debug, Clone)]
 struct ProtoComponentBranch {
+    ended: bool,
     inbox: HashMap<PortId, Payload>,
     state: ComponentState,
 }
@@ -319,7 +320,7 @@ impl Connector {
                     cu.proto_components.keys()
                 );
                 // consume native
-                Ok(Some(branching_native.collapse_with(&predicate)))
+                Ok(Some(branching_native.collapse_with(&mut *cu.logger, &predicate)))
             }
         };
         log!(cu.logger, "Sync round ending! Cleaning up");
@@ -364,6 +365,7 @@ impl Connector {
         for (&proto_component_id, proto_component) in branching_proto_components.iter_mut() {
             let BranchingProtoComponent { ports, branches } = proto_component;
             let mut swap = HashMap::default();
+            // initially, no components have .ended==true
             let mut blocked = HashMap::default();
             // drain from branches --> blocked
             let cd = CyclicDrainer::new(branches, &mut swap, &mut blocked);
@@ -651,6 +653,12 @@ impl BranchingNative {
                 assert!(was.is_none());
                 branch.to_get.remove(&getter);
                 if branch.to_get.is_empty() {
+                    log!(
+                        cu.logger,
+                        "new native solution with {:?} (to_get.is_empty()) with gotten {:?}",
+                        &predicate,
+                        &branch.gotten
+                    );
                     let route = Route::LocalComponent(ComponentId::Native);
                     solution_storage.submit_and_digest_subtree_solution(
                         &mut *cu.logger,
@@ -715,10 +723,17 @@ impl BranchingNative {
             }
         }
     }
-    fn collapse_with(self, solution_predicate: &Predicate) -> RoundOk {
+    fn collapse_with(self, logger: &mut dyn Logger, solution_predicate: &Predicate) -> RoundOk {
+        log!(
+            logger,
+            "Collapsing native with {} branch preds {:?}",
+            self.branches.len(),
+            self.branches.keys()
+        );
         for (branch_predicate, branch) in self.branches {
-            if solution_predicate.satisfies(&branch_predicate) {
+            if branch.to_get.is_empty() && solution_predicate.satisfies(&branch_predicate) {
                 let NativeBranch { index, gotten, .. } = branch;
+                log!(logger, "Collapsed native has gotten {:?}", &gotten);
                 return RoundOk { batch_index: index, gotten };
             }
         }
@@ -771,6 +786,7 @@ impl BranchingProtoComponent {
                         Route::LocalComponent(ComponentId::Proto(proto_component_id)),
                         predicate.clone(),
                     );
+                    branch.ended = true;
                     // move to "blocked"
                     drainer.add_output(predicate, branch);
                 }
@@ -832,6 +848,11 @@ impl BranchingProtoComponent {
         // partition drain from branches -> {unblocked, blocked}
         log!(logger, "visiting {} blocked branches...", branches.len());
         for (predicate, mut branch) in branches.drain() {
+            if branch.ended {
+                log!(logger, "Skipping ended branch with {:?}", &predicate);
+                blocked.insert(predicate, branch);
+                continue;
+            }
             use CommonSatResult as Csr;
             log!(logger, "visiting branch with pred {:?}", &predicate);
             match predicate.common_satisfier(&send_payload_msg.predicate) {
@@ -885,7 +906,7 @@ impl BranchingProtoComponent {
     fn collapse_with(self, solution_predicate: &Predicate) -> ProtoComponent {
         let BranchingProtoComponent { ports, branches } = self;
         for (branch_predicate, branch) in branches {
-            if branch_predicate.satisfies(solution_predicate) {
+            if branch.ended && branch_predicate.satisfies(solution_predicate) {
                 let ProtoComponentBranch { state, .. } = branch;
                 return ProtoComponent { state, ports };
             }
@@ -893,7 +914,7 @@ impl BranchingProtoComponent {
         panic!("ProtoComponent had no branches matching pred {:?}", solution_predicate);
     }
     fn initial(ProtoComponent { state, ports }: ProtoComponent) -> Self {
-        let branch = ProtoComponentBranch { inbox: Default::default(), state };
+        let branch = ProtoComponentBranch { inbox: Default::default(), state, ended: false };
         Self { ports, branches: hashmap! { Predicate::default() => branch  } }
     }
 }