diff --git a/artio-system-tests/src/test/java/uk/co/real_logic/artio/system_tests/SystemTestUtil.java b/artio-system-tests/src/test/java/uk/co/real_logic/artio/system_tests/SystemTestUtil.java
index 84bc4fc74b..f3e6c62f6e 100644
--- a/artio-system-tests/src/test/java/uk/co/real_logic/artio/system_tests/SystemTestUtil.java
+++ b/artio-system-tests/src/test/java/uk/co/real_logic/artio/system_tests/SystemTestUtil.java
@@ -733,6 +733,11 @@ static void assertEngineSubscriptionCaughtUpToLibraryPublication(
             countersReader.forEach((counterId, typeId, keyBuffer, label) ->
                 subPosMatcher.tryMatch(counterId, typeId, keyBuffer));
 
+            if (!subPosMatcher.hasCounterId())
+            {
+                throw new IllegalStateException("did not match counter: " + subPosMatcher);
+            }
+
             assertEventuallyTrue(
                 () ->
                 {