diff --git a/tests/test_merkle_sync.c b/tests/test_merkle_sync.c
index c22ce9f3..b857e841 100644
--- a/tests/test_merkle_sync.c
+++ b/tests/test_merkle_sync.c
@@ -969,6 +969,9 @@ struct str_state {
     struct UTUN_INSTANCE*   inst[STRESS_N];
     struct ms_data          data[STRESS_N];
     struct ms_test_ctx      ctx[STRESS_N];
+    uint32_t               versions[STRESS_N]; /* Последняя версия каждого владельца записи. */
+    unsigned int           observer_starts[2];
+    uint64_t               spam_started_us;
     void*                   global_timeout;   /* setup: links-up timeout */
     void*                   safety_timer;     /* spam+converge safety */
     void*                   stop_timer;       /* spam stop */
@@ -996,9 +999,14 @@ static void _str_verify(void);
 static void _str_fail_timeout(void* arg);
 
 static void _str_sync_done(uint64_t peer, const char* ns, int result, void* arg) {
-    (void)peer; (void)ns; (void)result;
     struct str_state* s = (struct str_state*)arg;
-    if (s) __sync_fetch_and_sub(&s->sync_pending, 1);
+    if (!s || s->phase != 0) return;
+    if (result != MT_OK) {
+        DEBUG_ERROR(DEBUG_CATEGORY_MEMBER_SYNC, "stress initial sync: peer=%016llx ns=%s result=%d",
+                    (unsigned long long)peer, ns, result);
+        s->phase = 2;
+    }
+    __sync_fetch_and_sub(&s->sync_pending, 1);
 }
 
 static void _str_spam_cb(void* arg);
@@ -1016,7 +1024,7 @@ static void _str_spam_cb(void* arg) {
 
     /* spammer: bump own member, sync to hub */
     uint64_t key = ((uint64_t)idx) << 60;
-    _data_insert(&gs->data[idx], key, (uint32_t)(gs->data[idx].count + 1));
+    _data_insert(&gs->data[idx], key, ++gs->versions[idx]);
     merkle_sync_recompute_path(gs->inst[idx], MT_DATA_MEMBERS, MS_NS_STRESS, key);
     merkle_sync_start(gs->inst[idx], MT_DATA_MEMBERS, gs->inst[STRESS_HUB]->node_id, MS_NS_STRESS, NULL, NULL);
 
@@ -1027,6 +1035,7 @@ static void _str_obs_spam_cb(void* arg) {
     if (!gs || !gs->spam_active) return;
     int idx = (int)(intptr_t)arg;
 
+    gs->observer_starts[idx - STRESS_OBS_A]++;
     merkle_sync_start(gs->inst[idx], MT_DATA_MEMBERS, gs->inst[STRESS_HUB]->node_id, MS_NS_STRESS, NULL, NULL);
 
     int delay_tb = ((rand() % 10) + 1) * 10;  /* 1-10ms */
@@ -1060,7 +1069,7 @@ static int _str_wait_for(const char* desc, int (*cond)(void), int timeout_tb) {
     uint64_t start = get_time_tb();
     while (!cond() && (get_time_tb() - start) < (uint64_t)timeout_tb && s->phase == 0)
         uasync_poll(s->ua, 1);
-    if (cond()) return 1;
+    if (s->phase == 0 && cond()) return 1;
     printf("  STRESS TIMEOUT: %s\n", desc); s->phase = 2;
     return 0;
 }
@@ -1144,14 +1153,15 @@ static int _str_init(void) {
     /* --- seed each instance with its own member; sync to hub --- */
     for (int i = 1; i < STRESS_N; i++) {
         uint64_t key = ((uint64_t)i) << 60;
-        _data_insert(&s->data[i], key, (uint32_t)i);
+        s->versions[i] = (uint32_t)i;
+        _data_insert(&s->data[i], key, s->versions[i]);
         merkle_sync_recompute_path(s->inst[i], MT_DATA_MEMBERS, MS_NS_STRESS, key);
     }
     /* initial sync: each spoke → hub */
     s->sync_pending = STRESS_N - 1;
     for (int i = 1; i < STRESS_N; i++)
         merkle_sync_start(s->inst[i], MT_DATA_MEMBERS, s->inst[STRESS_HUB]->node_id, MS_NS_STRESS, _str_sync_done, s);
-    _str_wait_for("initial sync", _str_cond_sync_done, STRESS_SYNC_TB);
+    if (!_str_wait_for("initial sync", _str_cond_sync_done, STRESS_SYNC_TB)) goto fail;
 
     /* observers: sync with hub too */
 
@@ -1192,7 +1202,9 @@ static void _str_stop_spam(void* arg) {
     if (!gs) return;
     gs->stop_timer = NULL;
     gs->spam_active = 0;
-    printf("  spam stopped\n");
+    printf("  spam stopped after %lluus; writer updates:", (unsigned long long)(get_time_us() - gs->spam_started_us));
+    for (int i = STRESS_SPAM_BEGIN; i <= STRESS_SPAM_END; i++) printf(" %u", gs->versions[i] - (uint32_t)i);
+    printf("; observer starts: %u %u\n", gs->observer_starts[0], gs->observer_starts[1]);
     /* короткий дренаж — даём in-flight спам-синкам утихнуть перед финальными раундами */
     gs->drain_timer = uasync_set_timeout(gs->ua, STRESS_DRAIN_TB, NULL, _str_drain_cb, "str_drain");
 }
@@ -1215,8 +1227,14 @@ static void _str_start_final_round(void) {
 }
 
 static void _str_final_done(uint64_t peer, const char* ns, int result, void* arg) {
-    (void)peer; (void)ns; (void)result; (void)arg;
-    if (!gs) return;
+    (void)arg;
+    if (!gs || gs->phase != 0) return;
+    if (result != MT_OK) {
+        DEBUG_ERROR(DEBUG_CATEGORY_MEMBER_SYNC, "stress final sync: round=%d peer=%016llx ns=%s result=%d",
+                    gs->final_round, (unsigned long long)peer, ns, result);
+        gs->phase = 2;
+        return;
+    }
     gs->final_pending--;
     if (gs->final_pending <= 0) _str_check_roots();
 }
@@ -1225,6 +1243,37 @@ static void _str_verify(void) {
     struct str_state* s = gs;
     int ok = 1;
 
+    // Нагрузка должна менять записи; равные корни сами по себе не доказывают доставку последних версий.
+    for (int owner = STRESS_SPAM_BEGIN; owner <= STRESS_SPAM_END; owner++) {
+        if (s->versions[owner] - (uint32_t)owner >= 10) continue;
+        DEBUG_ERROR(DEBUG_CATEGORY_MEMBER_SYNC, "stress writer=%d made fewer than ten updates", owner);
+        ok = 0;
+    }
+    if (s->observer_starts[0] < 10 || s->observer_starts[1] < 10) {
+        DEBUG_ERROR(DEBUG_CATEGORY_MEMBER_SYNC, "stress observer starts too few: %u %u",
+                    s->observer_starts[0], s->observer_starts[1]);
+        ok = 0;
+    }
+    for (int i = 0; i < STRESS_N && ok; i++) {
+        if (s->data[i].count != STRESS_N - 1) {
+            DEBUG_ERROR(DEBUG_CATEGORY_MEMBER_SYNC, "stress inst=%d items=%d expected=%d", i, s->data[i].count, STRESS_N - 1);
+            ok = 0;
+            break;
+        }
+        for (int owner = 1; owner < STRESS_N && ok; owner++) {
+            uint64_t key = ((uint64_t)owner) << 60;
+            int found = 0;
+            for (int j = 0; j < s->data[i].count; j++) {
+                if (s->data[i].items[j].key == key && s->data[i].items[j].val == s->versions[owner]) { found = 1; break; }
+            }
+            if (!found) {
+                DEBUG_ERROR(DEBUG_CATEGORY_MEMBER_SYNC, "stress inst=%d missing final version: owner=%d version=%u",
+                            i, owner, s->versions[owner]);
+                ok = 0;
+            }
+        }
+    }
+
     /* tree sizes match pairwise */
     int na = _db_count_rows(s->inst[STRESS_HUB]->topo_sqlite_db, MS_NS_STRESS);
     for (int i = 1; i < STRESS_N && ok; i++) {
@@ -1314,6 +1363,7 @@ static void test_stress_spam(void) {
 
     /* --- start spam --- */
     s->spam_active = 1;
+    s->spam_started_us = get_time_us();
     srand(12345);
     for (int i = STRESS_SPAM_BEGIN; i <= STRESS_SPAM_END; i++) {
         /* stagger initial delays */