diff --git a/app/utils.py b/app/utils.py
index 75f301b72..554ccc83c 100644
--- a/app/utils.py
+++ b/app/utils.py
@@ -651,9 +651,9 @@ def merge_jsonlike(source, destination):
         return True
 
     def merge_lists(source, destination):
-        last_dest_idx = len(destination) - 1
+        last_src_idx = len(source) - 1
         for idx, item in enumerate(destination):
-            if idx <= last_dest_idx:
+            if idx <= last_src_idx:
                 # assign destination value if can't be merged into source
                 if merge_items(source[idx], destination[idx]) is False:
                     source[idx] = destination[idx]
diff --git a/tests/app/test_utils.py b/tests/app/test_utils.py
index b198cf1b0..1f5cd0c8e 100644
--- a/tests/app/test_utils.py
+++ b/tests/app/test_utils.py
@@ -630,6 +630,8 @@ def test_get_sample_template_returns_template(template_type):
     ([{"b": "c"}], [{"b": "e"}], [{"b": "e"}]),
     # if nested dicts in lists have different keys, additive behaviour
     ([{"b": "c"}], [{"d": {"e": "f"}}], [{"b": "c", "d": {"e": "f"}}]),
+    # if dicts in destination list but not source, they just get added to end of source
+    ([{"a": "b"}], [{"a": "b"}, {"a": "b"}, {"c": "d"}], [{"a": "b"}, {"a": "b"}, {"c": "d"}]),
     # merge a dict with a null object returns that dict (does not work the other way round)
     ({"a": {"b": "c"}}, None, {"a": {"b": "c"}}),
     # double nested dicts, new adds new Boolean key: value, additive behaviour