diff --git a/doc/release_notes.rst b/doc/release_notes.rst
index 8326f615..b782a6df 100644
--- a/doc/release_notes.rst
+++ b/doc/release_notes.rst
@@ -174,6 +174,8 @@ Upcoming Release
 
 * Fix index of existing capacities in `add_power_capacities_installed_before_baseyear` with `m` option.
 
+* Fix custom busmap read in `cluster_network`.
+
 PyPSA-Eur 0.10.0 (19th February 2024)
 =====================================
 
diff --git a/scripts/cluster_network.py b/scripts/cluster_network.py
index 903cbe9b..b0b73ade 100644
--- a/scripts/cluster_network.py
+++ b/scripts/cluster_network.py
@@ -519,8 +519,8 @@ if __name__ == "__main__":
         custom_busmap = params.custom_busmap
         if custom_busmap:
             custom_busmap = pd.read_csv(
-                snakemake.input.custom_busmap, index_col=0, squeeze=True
-            )
+                snakemake.input.custom_busmap, index_col=0
+            ).squeeze()
             custom_busmap.index = custom_busmap.index.astype(str)
             logger.info(f"Imported custom busmap from {snakemake.input.custom_busmap}")