diff --git a/xcp_d/workflows/outputs.py b/xcp_d/workflows/outputs.py
index f6bce9060..d7c7962ca 100644
--- a/xcp_d/workflows/outputs.py
+++ b/xcp_d/workflows/outputs.py
@@ -423,11 +423,7 @@ def _custom_to_source(out_file):
     # fmt:on
 
     confounds_src = pe.Node(
-        InferBIDSURIs(
-            numinputs=3 if custom_confounds_file else 2,
-            dataset_name="preprocessed",
-            dataset_path=fmri_dir,
-        ),
+        niu.Merge(numinputs=3 if custom_confounds_file else 2),
         name="confounds_src",
         run_without_submitting=True,
         mem_gb=1,