diff --git a/.semversioner/next-release/patch-20250224201440103182.json b/.semversioner/next-release/patch-20250224201440103182.json
new file mode 100644
index 00000000..94254328
--- /dev/null
+++ b/.semversioner/next-release/patch-20250224201440103182.json
@@ -0,0 +1,4 @@
+{
+  "type": "patch",
+  "description": "Properly increment text unit IDs during updates."
+}
diff --git a/graphrag/index/update/incremental_index.py b/graphrag/index/update/incremental_index.py
index 9eba64ab..3671d97e 100644
--- a/graphrag/index/update/incremental_index.py
+++ b/graphrag/index/update/incremental_index.py
@@ -301,6 +301,10 @@ def _update_and_merge_text_units(
             lambda x: [entity_id_mapping.get(i, i) for i in x] if x is not None else x
         )
 
+    initial_id = old_text_units["human_readable_id"].max() + 1
+    delta_text_units["human_readable_id"] = np.arange(
+        initial_id, initial_id + len(delta_text_units)
+    )
     # Merge the final text units
     return pd.concat([old_text_units, delta_text_units], ignore_index=True, copy=False)