diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3210f95f..16a59764 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+# [5.1.1][] (2022-09-01)
+
+## Fixed
+
+- [#539][] - Fixed a caching error in default values.
+
 # [5.1.0][] (2022-07-28)
 
 ## Added
@@ -1112,6 +1118,7 @@ Example.run
 
 - Initial release.
 
+  [5.1.1]: https://github.com/AaronLasseigne/active_interaction/compare/v5.1.0...v5.1.1
   [5.1.0]: https://github.com/AaronLasseigne/active_interaction/compare/v5.0.0...v5.1.0
   [5.0.0]: https://github.com/AaronLasseigne/active_interaction/compare/v4.1.0...v5.0.0
   [4.1.0]: https://github.com/AaronLasseigne/active_interaction/compare/v4.0.6...v4.1.0
@@ -1339,3 +1346,4 @@ Example.run
   [#503]: https://github.com/AaronLasseigne/active_interaction/issues/503
   [#536]: https://github.com/AaronLasseigne/active_interaction/issues/536
   [#537]: https://github.com/AaronLasseigne/active_interaction/issues/537
+  [#539]: https://github.com/AaronLasseigne/active_interaction/issues/539
diff --git a/lib/active_interaction/filter.rb b/lib/active_interaction/filter.rb
index 39868867..0e49bb57 100644
--- a/lib/active_interaction/filter.rb
+++ b/lib/active_interaction/filter.rb
@@ -112,24 +112,21 @@ def process(value, context)
     # @raise [NoDefaultError] If the default is missing.
     # @raise [InvalidDefaultError] If the default is invalid.
     def default(context = nil)
-      return @default if defined?(@default)
-
       raise NoDefaultError, name unless default?
 
       value = raw_default(context)
       raise InvalidDefaultError, "#{name}: #{value.inspect}" if value.is_a?(GroupedInput)
 
-      @default =
-        if value.nil?
-          nil
-        else
-          default = process(value, context)
-          if default.errors.any? && default.errors.first.is_a?(Filter::Error)
-            raise InvalidDefaultError, "#{name}: #{value.inspect}"
-          end
-
-          default.value
+      if value.nil?
+        nil
+      else
+        default = process(value, context)
+        if default.errors.any? && default.errors.first.is_a?(Filter::Error)
+          raise InvalidDefaultError, "#{name}: #{value.inspect}"
         end
+
+        default.value
+      end
     end
 
     # Get the description.
diff --git a/lib/active_interaction/version.rb b/lib/active_interaction/version.rb
index 10344237..0cf29480 100644
--- a/lib/active_interaction/version.rb
+++ b/lib/active_interaction/version.rb
@@ -4,5 +4,5 @@ module ActiveInteraction
   # The version number.
   #
   # @return [Gem::Version]
-  VERSION = Gem::Version.new('5.1.0')
+  VERSION = Gem::Version.new('5.1.1')
 end
diff --git a/spec/active_interaction/filter_spec.rb b/spec/active_interaction/filter_spec.rb
index e0ae3eae..eea6949c 100644
--- a/spec/active_interaction/filter_spec.rb
+++ b/spec/active_interaction/filter_spec.rb
@@ -36,4 +36,25 @@
       end
     end
   end
+
+  describe '#default' do
+    subject(:filter) { ActiveInteraction::IntegerFilter.new(:test, default: default) }
+
+    context 'when it is a value' do
+      let(:default) { 1 }
+
+      it 'returns the default' do
+        expect(filter.default).to be 1
+      end
+    end
+
+    context 'when it is a proc' do
+      let(:default) { -> { i + 1 } }
+
+      it 'returns the default' do
+        expect(filter.default(double(i: 0))).to be 1 # rubocop:disable RSpec/VerifiedDoubles
+        expect(filter.default(double(i: 1))).to be 2 # rubocop:disable RSpec/VerifiedDoubles
+      end
+    end
+  end
 end