diff --git a/smocore/qutex.cpp b/smocore/qutex.cpp
index 3fe5c88..967fe73 100644
--- a/smocore/qutex.cpp
+++ b/smocore/qutex.cpp
@@ -123,8 +123,25 @@ void Qutex::backoff(
 			": backoff called on empty queue - this should never happen");
 	}
 
+	/* Check if failedAcquirer is at the front of the queue with
+	* nRequiredLocks == 1. This should never happen because an
+	* acquirer at the front of the queue with nRequiredLocks == 1
+	* should always succeed.
+	*/
+	const LockerAndInvokerBase& oldFront = *queue.front();
+	if (oldFront == failedAcquirer && nRequiredLocks == 1)
+	{
+		lock.release();
+
+		throw std::runtime_error(
+			std::string(__func__) +
+			": Failed acquirer is at front of queue with nRequiredLocks==1 - "
+			"acquirer at front of queue with nRequiredLocks==1 should always "
+			"succeed.");
+	}
+
 	// Rotate queue members if failedAcquirer is at front of queue
-	if ((*queue.front()) == failedAcquirer && nQItems > 1)
+	if (oldFront == failedAcquirer && nQItems > 1)
 	{
 		/**	EXPLANATION:
 		 * Rotate the top LockSet.size() items in the queue by moving