diff --git a/libs/bits/bit_array.go b/libs/bits/bit_array.go
index ad4efe31540..18daf50119c 100644
--- a/libs/bits/bit_array.go
+++ b/libs/bits/bit_array.go
@@ -264,9 +264,17 @@ func (bA *BitArray) PickRandom() (int, bool) {
 func (bA *BitArray) getNumTrueIndices() int {
 	count := 0
 	numElems := len(bA.Elems)
-	for i := 0; i < numElems; i++ {
+	// handle all elements except the last one
+	for i := 0; i < numElems-1; i++ {
 		count += bits.OnesCount64(bA.Elems[i])
 	}
+	// handle last element
+	numFinalBits := bA.Bits - (numElems-1)*64
+	for i := 0; i < numFinalBits; i++ {
+		if (bA.Elems[numElems-1] & (uint64(1) << uint64(i))) > 0 {
+			count++
+		}
+	}
 	return count
 }
 
diff --git a/libs/bits/bit_array_test.go b/libs/bits/bit_array_test.go
index dce587ca00f..ad6a3a9f00e 100644
--- a/libs/bits/bit_array_test.go
+++ b/libs/bits/bit_array_test.go
@@ -173,6 +173,8 @@ func TestGetNumTrueIndices(t *testing.T) {
 		require.NoError(t, err)
 		result := bitArr.getNumTrueIndices()
 		require.Equal(t, tc.ExpectedResult, result, "for input %s, expected %d, got %d", tc.Input, tc.ExpectedResult, result)
+		result = bitArr.Not().getNumTrueIndices()
+		require.Equal(t, bitArr.Bits-result, bitArr.getNumTrueIndices())
 	}
 }