diff --git a/ntp_core.c b/ntp_core.c
index b73309e..7a21f5e 100644
--- a/ntp_core.c
+++ b/ntp_core.c
@@ -1907,12 +1907,17 @@ process_response(NCR_Instance inst, NTP_Local_Address *local_addr,
 
     /* Test A requires that the minimum estimate of the peer delay is not
        larger than the configured maximum, in both client modes that the server
-       processing time is sane, and in interleaved symmetric mode that the
+       processing time is sane, in interleaved client/server mode that the
+       previous response was not in basic mode (which prevents using timestamps
+       that minimise delay error), and in interleaved symmetric mode that the
        measured delay and intervals between remote timestamps don't indicate
        a missed response */
     testA = sample.peer_delay - sample.peer_dispersion <= inst->max_delay &&
             precision <= inst->max_delay &&
             !(inst->mode == MODE_CLIENT && response_time > MAX_SERVER_INTERVAL) &&
+            !(inst->mode == MODE_CLIENT && interleaved_packet &&
+              UTI_IsZeroTimespec(&inst->prev_local_tx.ts) &&
+              UTI_CompareTimespecs(&local_transmit.ts, &inst->local_tx.ts) == 0) &&
             !(inst->mode == MODE_ACTIVE && interleaved_packet &&
               (sample.peer_delay > 0.5 * prev_remote_poll_interval ||
                UTI_CompareNtp64(&message->receive_ts, &message->transmit_ts) <= 0 ||
diff --git a/test/simulation/122-xleave b/test/simulation/122-xleave
index bc4c3a7..c19063a 100755
--- a/test/simulation/122-xleave
+++ b/test/simulation/122-xleave
@@ -15,10 +15,11 @@ check_chronyd_exit || test_fail
 check_source_selection || test_fail
 check_sync || test_fail
 
-check_file_messages "111 111 1111.* 4I [DKH] [DKH]\$" 0 0 measurements.log || test_fail
+check_file_messages "111 111 .111.* 4I [DKH] [DKH]\$" 0 0 measurements.log || test_fail
 rm -f tmp/measurements.log
 
 server_conf=""
+max_sync_time=270
 
 run_test || test_fail
 check_chronyd_exit || test_fail
@@ -28,6 +29,7 @@ check_sync || test_fail
 
 check_file_messages "111 111 1111.* 4B [DKH] [DKH]\$" 2 2 measurements.log || test_fail
 check_file_messages "111 111 1111.* 4I [DKH] [DKH]\$" 30 200 measurements.log || test_fail
+check_file_messages "111 111 0111.* 4I [DKH] [DKH]\$" 1 1 measurements.log || test_fail
 rm -f tmp/measurements.log
 
 clients=2
diff --git a/test/unit/ntp_core.c b/test/unit/ntp_core.c
index 0d9c3a7..1d92ebf 100644
--- a/test/unit/ntp_core.c
+++ b/test/unit/ntp_core.c
@@ -496,7 +496,10 @@ test_unit(void)
 
       send_request(inst1);
       process_request(&remote_addr);
-      proc_response(inst1, 1, 1, 1, 0);
+      proc_response(inst1,
+                    !source.params.interleaved || source.params.version != 4 ||
+                      inst1->mode == MODE_ACTIVE || j != 2,
+                    1, 1, 0);
       advance_time(1 << inst1->local_poll);
     }