diff --git a/src/ffx/ffx_controller.py b/src/ffx/ffx_controller.py
index 9065b32..d142860 100644
--- a/src/ffx/ffx_controller.py
+++ b/src/ffx/ffx_controller.py
@@ -202,7 +202,7 @@ class FfxController():
                             + f":{CropFilter.OFFSET_X_KEY}"
                             + f":{CropFilter.OFFSET_Y_KEY}")
     
-            filterParamTokens.extend(cropParams)
+            filterParamTokens.append(cropParams)
 
         filterParamTokens.extend(denoiseFilters[0]['tokens'] if denoiseFilters else [])