diff --git a/lib/open_rtb_ecto/v2/bid_request/brand_version.ex b/lib/open_rtb_ecto/v2/bid_request/brand_version.ex
index a849a65..df51dee 100644
--- a/lib/open_rtb_ecto/v2/bid_request/brand_version.ex
+++ b/lib/open_rtb_ecto/v2/bid_request/brand_version.ex
@@ -20,7 +20,6 @@ defmodule OpenRtbEcto.V2.BidRequest.BrandVersion do
     version
     |> cast(attrs, [:brand, :version])
     |> OpenRtbEcto.safe_cast_ext(attrs)
-    |> validate_required([:brand])
   end
 
   def changeset(version, _), do: change(version)
diff --git a/lib/open_rtb_ecto/v2/bid_request/user_agent.ex b/lib/open_rtb_ecto/v2/bid_request/user_agent.ex
index cca02ef..44f9f88 100644
--- a/lib/open_rtb_ecto/v2/bid_request/user_agent.ex
+++ b/lib/open_rtb_ecto/v2/bid_request/user_agent.ex
@@ -29,9 +29,17 @@ defmodule OpenRtbEcto.V2.BidRequest.UserAgent do
     user_agent
     |> cast(attrs, [:mobile, :architecture, :bitness, :model, :source])
     |> OpenRtbEcto.safe_cast_ext(attrs)
-    |> cast_embed(:browsers)
+    |> safe_cast_browsers(attrs)
     |> cast_embed(:platform)
   end
 
   def changeset(user_agent, _), do: change(user_agent)
+
+  defp safe_cast_browsers(changeset, %{"browsers" => browsers}) when is_list(browsers),
+    do: cast_embed(changeset, :browsers)
+
+  defp safe_cast_browsers(changeset, %{browsers: browsers}) when is_list(browsers),
+    do: cast_embed(changeset, :browsers)
+
+  defp safe_cast_browsers(changeset, _attrs), do: changeset
 end
diff --git a/test/open_rtb_ecto/v2/bid_request_test.exs b/test/open_rtb_ecto/v2/bid_request_test.exs
index 38aec34..feb1e71 100644
--- a/test/open_rtb_ecto/v2/bid_request_test.exs
+++ b/test/open_rtb_ecto/v2/bid_request_test.exs
@@ -134,6 +134,20 @@ defmodule OpenRtbEcto.V2.BidRequestTest do
               }} = OpenRtbEcto.cast(BidRequest, data)
     end
 
+    test "structured user-agent with null browsers and empty brand" do
+      data = TestHelper.test_data("v2/request", "structured-ua.json")
+
+      data =
+        put_in(data, ["device", "sua"], %{
+          "browsers" => nil,
+          "platform" => %{"brand" => ""},
+          "source" => 0
+        })
+
+      assert {:ok, %BidRequest{device: %Device{sua: %UserAgent{browsers: [], source: 0}}}} =
+               OpenRtbEcto.cast(BidRequest, data)
+    end
+
     test "multiple imps" do
       data = TestHelper.test_data("v2/request", "multi-imp.json")
       assert {:ok, %BidRequest{} = req} = OpenRtbEcto.cast(BidRequest, data)