diff --git a/cpp/ql/test/library-tests/dataflow/taint-tests/localTaint.expected b/cpp/ql/test/library-tests/dataflow/taint-tests/localTaint.expected
index 907cccd197b..85fc3526dc7 100644
--- a/cpp/ql/test/library-tests/dataflow/taint-tests/localTaint.expected
+++ b/cpp/ql/test/library-tests/dataflow/taint-tests/localTaint.expected
@@ -8090,20 +8090,20 @@
 | vector.cpp:520:25:520:31 | call to vector | vector.cpp:523:8:523:9 | vs |  |
 | vector.cpp:520:25:520:31 | call to vector | vector.cpp:524:8:524:9 | vs |  |
 | vector.cpp:520:25:520:31 | call to vector | vector.cpp:526:8:526:9 | vs |  |
-| vector.cpp:520:25:520:31 | call to vector | vector.cpp:532:8:532:9 | vs |  |
-| vector.cpp:520:25:520:31 | call to vector | vector.cpp:533:2:533:2 | vs |  |
+| vector.cpp:520:25:520:31 | call to vector | vector.cpp:539:8:539:9 | vs |  |
+| vector.cpp:520:25:520:31 | call to vector | vector.cpp:540:2:540:2 | vs |  |
 | vector.cpp:520:30:520:30 | 0 | vector.cpp:520:25:520:31 | call to vector | TAINT |
 | vector.cpp:523:8:523:9 | ref arg vs | vector.cpp:524:8:524:9 | vs |  |
 | vector.cpp:523:8:523:9 | ref arg vs | vector.cpp:526:8:526:9 | vs |  |
-| vector.cpp:523:8:523:9 | ref arg vs | vector.cpp:532:8:532:9 | vs |  |
-| vector.cpp:523:8:523:9 | ref arg vs | vector.cpp:533:2:533:2 | vs |  |
+| vector.cpp:523:8:523:9 | ref arg vs | vector.cpp:539:8:539:9 | vs |  |
+| vector.cpp:523:8:523:9 | ref arg vs | vector.cpp:540:2:540:2 | vs |  |
 | vector.cpp:523:8:523:9 | vs | vector.cpp:523:10:523:10 | call to operator[] | TAINT |
 | vector.cpp:524:8:524:9 | ref arg vs | vector.cpp:526:8:526:9 | vs |  |
-| vector.cpp:524:8:524:9 | ref arg vs | vector.cpp:532:8:532:9 | vs |  |
-| vector.cpp:524:8:524:9 | ref arg vs | vector.cpp:533:2:533:2 | vs |  |
+| vector.cpp:524:8:524:9 | ref arg vs | vector.cpp:539:8:539:9 | vs |  |
+| vector.cpp:524:8:524:9 | ref arg vs | vector.cpp:540:2:540:2 | vs |  |
 | vector.cpp:524:8:524:9 | vs | vector.cpp:524:10:524:10 | call to operator[] | TAINT |
-| vector.cpp:526:8:526:9 | ref arg vs | vector.cpp:532:8:532:9 | vs |  |
-| vector.cpp:526:8:526:9 | ref arg vs | vector.cpp:533:2:533:2 | vs |  |
+| vector.cpp:526:8:526:9 | ref arg vs | vector.cpp:539:8:539:9 | vs |  |
+| vector.cpp:526:8:526:9 | ref arg vs | vector.cpp:540:2:540:2 | vs |  |
 | vector.cpp:526:8:526:9 | vs | vector.cpp:526:11:526:15 | call to begin | TAINT |
 | vector.cpp:526:11:526:15 | call to begin | vector.cpp:526:3:526:17 | ... = ... |  |
 | vector.cpp:526:11:526:15 | call to begin | vector.cpp:527:9:527:10 | it |  |
@@ -8128,5 +8128,5 @@
 | vector.cpp:530:3:530:4 | ref arg it | vector.cpp:531:9:531:10 | it |  |
 | vector.cpp:530:9:530:14 | call to source | vector.cpp:530:3:530:4 | ref arg it | TAINT |
 | vector.cpp:531:9:531:10 | it | vector.cpp:531:8:531:8 | call to operator* | TAINT |
-| vector.cpp:532:8:532:9 | ref arg vs | vector.cpp:533:2:533:2 | vs |  |
-| vector.cpp:532:8:532:9 | vs | vector.cpp:532:10:532:10 | call to operator[] | TAINT |
+| vector.cpp:539:8:539:9 | ref arg vs | vector.cpp:540:2:540:2 | vs |  |
+| vector.cpp:539:8:539:9 | vs | vector.cpp:539:10:539:10 | call to operator[] | TAINT |
diff --git a/cpp/ql/test/library-tests/dataflow/taint-tests/vector.cpp b/cpp/ql/test/library-tests/dataflow/taint-tests/vector.cpp
index 4bc1073634a..ca8240c8999 100644
--- a/cpp/ql/test/library-tests/dataflow/taint-tests/vector.cpp
+++ b/cpp/ql/test/library-tests/dataflow/taint-tests/vector.cpp
@@ -523,12 +523,19 @@ void test_vector_iterator() {
 		sink(vs[1]);
 		sink(vs[source()]); // $ MISSING: ast,ir
 
-		it = vs.begin();
+		it = vs.begin(); // (1)
 		sink(*it);
 		it += 1;
 		sink(*it);
-		it += source();
-		sink(*it); // $ ast,ir
-		sink(vs[1]); // $ SPURIOUS: ir
+		it += source(); // (2)
+		sink(*it); // $ ast,ir // (3)
+		// This FP happens because of the following flows:
+		// 1. There's a write to the iterator at (2)
+		// 2. This write propagates to `it` on the next line at (3)
+		// 3. There's a taint step from `it` to `*it` at (3)
+		// 4. The `*it` is seen as a use of `vs` because of (1).
+		// 5. There's use-use flow from `*it` at (3) (which is a use of `vs`) to `vs` at (4)
+		// 6. There's a taint step from vs to vs[1]
+		sink(vs[1]); // $ SPURIOUS: ir // (4)
 	}
 }