diff --git a/src/runtime2/component/component.rs b/src/runtime2/component/component.rs
index 67dd569364fdf0803e7cbd6e13012cdac1b22975..d62e12376dc8a3aad288ca6dd4688da39fd99750 100644
--- a/src/runtime2/component/component.rs
+++ b/src/runtime2/component/component.rs
@@ -278,6 +278,7 @@ pub(crate) fn default_send_data_message(
     let port_handle = comp_ctx.get_port_handle(transmitting_port_id);
     let port_info = comp_ctx.get_port_mut(port_handle);
     port_info.last_instruction = port_instruction;
+    port_info.last_registered_round = Some(consensus.round_number());
 
     let port_info = comp_ctx.get_port(port_handle);
     debug_assert_eq!(port_info.kind, PortKind::Putter);
@@ -511,9 +512,10 @@ pub(crate) fn default_handle_received_data_message(
     }
 
     // Modify last-known location where port instruction was retrieved
-    let port_info = comp_ctx.get_port(port_handle);
+    let port_info = comp_ctx.get_port_mut(port_handle);
     debug_assert_ne!(port_info.last_instruction, PortInstruction::None); // set by caller
     debug_assert!(port_info.state.is_open()); // checked by caller
+    port_info.last_registered_round = Some(message.sync_header.sync_round);
 
     // Check if there are any more messages in the backup buffer
     for message_index in 0..inbox_backup.len() {
@@ -591,6 +593,7 @@ pub(crate) fn default_handle_control_message(
             } else {
                 // Respond to the message
                 let port_info = comp_ctx.get_port(port_handle);
+                let last_registered_round = port_info.last_registered_round;
                 let last_instruction = port_info.last_instruction;
                 let port_has_had_message = port_info.received_message_for_sync;
                 default_send_ack(message.id, peer_handle, sched_ctx, comp_ctx);
@@ -607,10 +610,11 @@ pub(crate) fn default_handle_control_message(
                 let port_was_used = last_instruction != PortInstruction::None;
 
                 if exec_state.mode.is_in_sync_block() {
-                    let closed_during_sync_round = content.closed_in_sync_round && port_was_used;
-                    let closed_before_sync_round = !content.closed_in_sync_round && !port_has_had_message && port_was_used;
+                    let round_has_succeeded = !content.closed_in_sync_round && last_registered_round == content.registered_round;
+                    let closed_during_sync_round = content.closed_in_sync_round;
+                    let closed_before_sync_round = ! closed_during_sync_round && !round_has_succeeded;
 
-                    if closed_during_sync_round || closed_before_sync_round {
+                    if (closed_during_sync_round || closed_before_sync_round) && port_was_used {
                         return Err((
                             last_instruction,
                             format!("Peer component (id:{}) shut down, so communication cannot (have) succeed(ed)", peer_comp_id.0)