diff --git a/src/mdbx.c b/src/mdbx.c
index 0f1d89c5..cd81e361 100644
--- a/src/mdbx.c
+++ b/src/mdbx.c
@@ -7699,7 +7699,7 @@ int mdbx_cursor_put(MDBX_cursor *mc, MDBX_val *key, MDBX_val *data,
         if (rc > 0) {
           rc = MDBX_NOTFOUND;
           mc->mc_ki[mc->mc_top]++;
-        } else {
+        } else if (unlikely(rc < 0 || (flags & MDBX_APPENDDUP) == 0)) {
           /* new key is <= last key */
           rc = MDBX_EKEYMISMATCH;
         }