diff --git a/lucene/core/src/java/org/apache/lucene/search/TwoPhaseDocIdSetIterator.java b/lucene/core/src/java/org/apache/lucene/search/TwoPhaseDocIdSetIterator.java
index baad57fb437..8c370d36035 100644
--- a/lucene/core/src/java/org/apache/lucene/search/TwoPhaseDocIdSetIterator.java
+++ b/lucene/core/src/java/org/apache/lucene/search/TwoPhaseDocIdSetIterator.java
@@ -73,9 +73,9 @@ public abstract class TwoPhaseDocIdSetIterator {
   public abstract DocIdSetIterator approximation();
 
   /** Return whether the current doc ID that the iterator is on matches. This
-   *  method should only be called when the iterator is positionned, ie. not
+   *  method should only be called when the iterator is positionned -- ie. not
    *  when {@link DocIdSetIterator#docID()} is {@code -1} or
-   *  {@link DocIdSetIterator#NO_MORE_DOCS}. */
+   *  {@link DocIdSetIterator#NO_MORE_DOCS} -- and at most once. */
   public abstract boolean matches() throws IOException;
 
 }
diff --git a/lucene/test-framework/src/java/org/apache/lucene/search/RandomApproximationQuery.java b/lucene/test-framework/src/java/org/apache/lucene/search/RandomApproximationQuery.java
index 62bd77ef73d..0bd63e24dcf 100644
--- a/lucene/test-framework/src/java/org/apache/lucene/search/RandomApproximationQuery.java
+++ b/lucene/test-framework/src/java/org/apache/lucene/search/RandomApproximationQuery.java
@@ -188,6 +188,7 @@ public class RandomApproximationQuery extends Query {
 
     private final DocIdSetIterator disi;
     private final RandomApproximation approximation;
+    private int lastDoc = -1;
 
     RandomTwoPhaseView(Random random, DocIdSetIterator disi) {
       this.disi = disi;
@@ -201,7 +202,14 @@ public class RandomApproximationQuery extends Query {
 
     @Override
     public boolean matches() throws IOException {
-      return approximation.doc == disi.docID();
+      if (approximation.docID() == -1 || approximation.docID() == DocIdSetIterator.NO_MORE_DOCS) {
+        throw new AssertionError("matches() should not be called on doc ID " + approximation.doc);
+      }
+      if (lastDoc == approximation.docID()) {
+        throw new AssertionError("matches() has been called twice on doc ID " + approximation.doc);
+      }
+      lastDoc = approximation.docID();
+      return approximation.docID() == disi.docID();
     }
 
   }