diff --git a/src/Mapper/Tree/Builder/ArrayNodeBuilder.php b/src/Mapper/Tree/Builder/ArrayNodeBuilder.php
index 2e3de61..87a32da 100644
--- a/src/Mapper/Tree/Builder/ArrayNodeBuilder.php
+++ b/src/Mapper/Tree/Builder/ArrayNodeBuilder.php
@@ -28,7 +28,7 @@ final class ArrayNodeBuilder implements NodeBuilder
     public function build(Shell $shell, RootNodeBuilder $rootBuilder): TreeNode
     {
         $type = $shell->type();
-        $value = $shell->hasValue() ? $shell->value() : null;
+        $value = $shell->value();
 
         assert($type instanceof ArrayType || $type instanceof NonEmptyArrayType || $type instanceof IterableType);
 
diff --git a/src/Mapper/Tree/Builder/IterableNodeBuilder.php b/src/Mapper/Tree/Builder/IterableNodeBuilder.php
index 08397d8..2b5fb0b 100644
--- a/src/Mapper/Tree/Builder/IterableNodeBuilder.php
+++ b/src/Mapper/Tree/Builder/IterableNodeBuilder.php
@@ -22,12 +22,10 @@ final class IterableNodeBuilder implements NodeBuilder
 
     public function build(Shell $shell, RootNodeBuilder $rootBuilder): TreeNode
     {
-        if ($shell->hasValue()) {
-            $value = $shell->value();
+        $value = $shell->value();
 
-            if (is_iterable($value) && ! is_array($value)) {
-                $shell = $shell->withValue(iterator_to_array($value));
-            }
+        if (is_iterable($value) && ! is_array($value)) {
+            $shell = $shell->withValue(iterator_to_array($value));
         }
 
         return $this->delegate->build($shell, $rootBuilder);
diff --git a/src/Mapper/Tree/Builder/ListNodeBuilder.php b/src/Mapper/Tree/Builder/ListNodeBuilder.php
index 97631b6..d37a4bc 100644
--- a/src/Mapper/Tree/Builder/ListNodeBuilder.php
+++ b/src/Mapper/Tree/Builder/ListNodeBuilder.php
@@ -27,7 +27,7 @@ final class ListNodeBuilder implements NodeBuilder
     public function build(Shell $shell, RootNodeBuilder $rootBuilder): TreeNode
     {
         $type = $shell->type();
-        $value = $shell->hasValue() ? $shell->value() : null;
+        $value = $shell->value();
 
         assert($type instanceof ListType || $type instanceof NonEmptyListType);
 
diff --git a/src/Mapper/Tree/Builder/ScalarNodeBuilder.php b/src/Mapper/Tree/Builder/ScalarNodeBuilder.php
index a976b8f..6ccb2db 100644
--- a/src/Mapper/Tree/Builder/ScalarNodeBuilder.php
+++ b/src/Mapper/Tree/Builder/ScalarNodeBuilder.php
@@ -23,7 +23,7 @@ final class ScalarNodeBuilder implements NodeBuilder
     public function build(Shell $shell, RootNodeBuilder $rootBuilder): TreeNode
     {
         $type = $shell->type();
-        $value = $shell->hasValue() ? $shell->value() : null;
+        $value = $shell->value();
 
         assert($type instanceof ScalarType);
 
diff --git a/src/Mapper/Tree/Builder/ShapedArrayNodeBuilder.php b/src/Mapper/Tree/Builder/ShapedArrayNodeBuilder.php
index 989f303..a64134a 100644
--- a/src/Mapper/Tree/Builder/ShapedArrayNodeBuilder.php
+++ b/src/Mapper/Tree/Builder/ShapedArrayNodeBuilder.php
@@ -28,7 +28,7 @@ final class ShapedArrayNodeBuilder implements NodeBuilder
     public function build(Shell $shell, RootNodeBuilder $rootBuilder): TreeNode
     {
         $type = $shell->type();
-        $value = $shell->hasValue() ? $shell->value() : null;
+        $value = $shell->value();
 
         assert($type instanceof ShapedArrayType);
 
diff --git a/src/Mapper/Tree/Builder/StrictNodeBuilder.php b/src/Mapper/Tree/Builder/StrictNodeBuilder.php
index f603804..52a5594 100644
--- a/src/Mapper/Tree/Builder/StrictNodeBuilder.php
+++ b/src/Mapper/Tree/Builder/StrictNodeBuilder.php
@@ -31,13 +31,7 @@ final class StrictNodeBuilder implements NodeBuilder
 
         if (! $shell->hasValue()) {
             if ($this->flexible) {
-                if ($type->accepts(null)) {
-                    return TreeNode::leaf($shell, null);
-                }
-
-                if ($type->accepts([])) {
-                    return TreeNode::leaf($shell, []);
-                }
+                return $this->delegate->build($shell->withValue(null), $rootBuilder);
             }
 
             throw new MissingNodeValue($type);
diff --git a/src/Mapper/Tree/Builder/UnionNodeBuilder.php b/src/Mapper/Tree/Builder/UnionNodeBuilder.php
index 702af7f..12e723a 100644
--- a/src/Mapper/Tree/Builder/UnionNodeBuilder.php
+++ b/src/Mapper/Tree/Builder/UnionNodeBuilder.php
@@ -25,7 +25,7 @@ final class UnionNodeBuilder implements NodeBuilder
     {
         $type = $shell->type();
 
-        if (! $type instanceof UnionType || ! $shell->hasValue()) {
+        if (! $type instanceof UnionType) {
             return $this->delegate->build($shell, $rootBuilder);
         }
 
diff --git a/tests/Integration/Mapping/Other/FlexibleMappingTest.php b/tests/Integration/Mapping/Other/FlexibleMappingTest.php
index 4ec777c..a7f3df5 100644
--- a/tests/Integration/Mapping/Other/FlexibleMappingTest.php
+++ b/tests/Integration/Mapping/Other/FlexibleMappingTest.php
@@ -436,8 +436,7 @@ final class FlexibleMappingTest extends IntegrationTest
         } catch (MappingError $exception) {
             $error = $exception->node()->children()['bar']->messages()[0];
 
-            self::assertSame('1655449641', $error->code());
-            self::assertSame('Cannot be empty and must be filled with a value matching type `string`.', (string)$error);
+            self::assertSame('Value *missing* is not a valid string.', (string)$error);
         }
     }
 }