diff --git a/src/controller/config_repl.c b/src/controller/config_repl.c
index 626edba..d3a5944 100644
--- a/src/controller/config_repl.c
+++ b/src/controller/config_repl.c
@@ -1011,16 +1011,24 @@ int conf_check_stale(const char *workdir, time_t stale_timeout_s)
 /* ── conf_trim_old_versions ─────────────────────── */
 
 typedef struct {
-    char   name[NAME_MAX];
-    time_t mtime;
+    char           name[NAME_MAX];
+    struct timespec mtime; /* st_mtim — nanosecond resolution. Trimming must
+                            * not tie on second-granularity st_mtime: configs
+                            * saved within the same second (rapid replication
+                            * or unit tests) would sort as equal and leave the
+                            * protected current slot as the only trim
+                            * candidate — which the pointer-protection skips,
+                            * so nothing ever gets pruned. */
 } ver_entry_t;
 
 static int ver_entry_cmp_desc(const void *a, const void *b)
 {
     const ver_entry_t *ea = (const ver_entry_t *)a;
     const ver_entry_t *eb = (const ver_entry_t *)b;
-    if (eb->mtime > ea->mtime) return 1;
-    if (eb->mtime < ea->mtime) return -1;
+    if (eb->mtime.tv_sec != ea->mtime.tv_sec)
+        return (eb->mtime.tv_sec > ea->mtime.tv_sec) ? 1 : -1;
+    if (eb->mtime.tv_nsec != ea->mtime.tv_nsec)
+        return (eb->mtime.tv_nsec > ea->mtime.tv_nsec) ? 1 : -1;
     return 0;
 }
 
@@ -1059,7 +1067,7 @@ void conf_trim_old_versions(const char *workdir, int keep_n)
         if (stat(full, &st) == 0) {
             strncpy(entries[n].name, e->d_name, NAME_MAX - 1);
             entries[n].name[NAME_MAX - 1] = '\0';
-            entries[n].mtime = st.st_mtime;
+            entries[n].mtime = st.st_mtim;
             n++;
         }
     }
diff --git a/src/controller/testsuite/test_config_repl.c b/src/controller/testsuite/test_config_repl.c
index 5c40758..a0336c0 100644
--- a/src/controller/testsuite/test_config_repl.c
+++ b/src/controller/testsuite/test_config_repl.c
@@ -61,8 +61,16 @@ static char tmpdir[256];
 
 static void cr_setup(void)
 {
-    snprintf(g_tmpdir, sizeof(g_tmpdir), "/tmp/test_cr_%d_%ld",
-             (int)getpid(), (long)time(NULL));
+    static unsigned int cr_seq;
+    /* Unique per invocation, not just per (pid, second): the 1000+ tests in
+     * this suite routinely run within the same wall-clock second, and a
+     * Unity assertion failure longjmps out of the test, skipping the
+     * cr_teardown() that would rm -rf the dir — so a reused path would make
+     * the next test silently inherit the previous one's cluster.bin.* files
+     * and conf/current (observed as a cascade: a leaked trim-test dir made
+     * test_conf_get_saved_tag_no_config read a real tag instead of 0). */
+    snprintf(g_tmpdir, sizeof(g_tmpdir), "/tmp/test_cr_%d_%u_%ld",
+             (int)getpid(), cr_seq++, (long)time(NULL));
     mkdir(g_tmpdir, 0700);
     /* conf_save_config() writes to workdir/name/conf — mirror that here */
     snprintf(g_instdir, sizeof(g_instdir), "%s/ctrl0", g_tmpdir);