diff --git a/app/models/spree/variant.rb b/app/models/spree/variant.rb
index f8711145d5..d2e8e5c4ea 100644
--- a/app/models/spree/variant.rb
+++ b/app/models/spree/variant.rb
@@ -63,8 +63,8 @@ module Spree
     }
 
     before_validation :set_cost_currency
-    before_validation :update_weight_from_unit_value, if: ->(v) { v.product.present? }
     before_validation :ensure_unit_value
+    before_validation :update_weight_from_unit_value, if: ->(v) { v.product.present? }
 
     after_save :save_default_price
     after_save :update_units
@@ -249,7 +249,8 @@ module Spree
     end
 
     def ensure_unit_value
-      return unless product&.variant_unit == "items" && unit_value.nil?
+      Bugsnag.notify("Trying to set unit_value to NaN") if unit_value&.nan?
+      return unless (product&.variant_unit == "items" && unit_value.nil?) || unit_value&.nan?
 
       self.unit_value = 1.0
     end
diff --git a/spec/models/spree/variant_spec.rb b/spec/models/spree/variant_spec.rb
index ccb1bcf3db..50214cf6b4 100644
--- a/spec/models/spree/variant_spec.rb
+++ b/spec/models/spree/variant_spec.rb
@@ -733,5 +733,13 @@ module Spree
         expect(variant.unit_value).to eq 1
       end
     end
+
+    context "trying to set an invalid unit_value" do
+      it "does not allow NaN" do
+        variant.update(unit_value: Float::NAN)
+
+        expect(variant.reload.unit_value).to eq(1.0)
+      end
+    end
   end
 end