diff --git a/src/core.c b/src/core.c
index e199fa5b..865f856b 100644
--- a/src/core.c
+++ b/src/core.c
@@ -9196,7 +9196,7 @@ int mdbx_txn_renew(MDBX_txn *txn) {
 
   rc = txn_renew(txn, MDBX_TXN_RDONLY);
   if (rc == MDBX_SUCCESS) {
-    txn->mt_owner = osal_thread_self();
+    tASSERT(txn, txn->mt_owner == osal_thread_self());
     DEBUG("renew txn %" PRIaTXN "%c %p on env %p, root page %" PRIaPGNO
           "/%" PRIaPGNO,
           txn->mt_txnid, (txn->mt_flags & MDBX_TXN_RDONLY) ? 'r' : 'w',