diff --git a/lib/broadway_cloud_pub_sub/pull_client.ex b/lib/broadway_cloud_pub_sub/pull_client.ex
index eb5e120..e87f19a 100644
--- a/lib/broadway_cloud_pub_sub/pull_client.ex
+++ b/lib/broadway_cloud_pub_sub/pull_client.ex
@@ -167,9 +167,7 @@ defmodule BroadwayCloudPubSub.PullClient do
     end
   end
 
-  defp decode_message(%{"data" => nil} = message), do: message
-
-  defp decode_message(%{"data" => encoded_data} = message) do
+  defp decode_message(%{"data" => encoded_data} = message) when is_binary(encoded_data) do
     %{message | "data" => Base.decode64!(encoded_data)}
   end