diff --git a/src/engine/IndexScan.cpp b/src/engine/IndexScan.cpp
index 5554bb62b8..f56123a42b 100644
--- a/src/engine/IndexScan.cpp
+++ b/src/engine/IndexScan.cpp
@@ -594,14 +594,14 @@ Result::Generator IndexScan::createPrefilteredJoinSide(
   }
   auto& prefetchedValues = innerState->prefetchedValues_;
   while (true) {
-    while (prefetchedValues.empty()) {
+    if (prefetchedValues.empty()) {
       if (innerState->doneFetching_) {
         co_return;
       }
       innerState->fetch();
+      AD_CORRECTNESS_CHECK(!prefetchedValues.empty() ||
+                           innerState->doneFetching_);
     }
-    AD_CORRECTNESS_CHECK(!prefetchedValues.empty() ||
-                         innerState->doneFetching_);
     // Make a defensive copy of the values to avoid modification during
     // iteration when yielding.
     auto copy = std::move(prefetchedValues);