diff --git a/CHANGELOG.md b/CHANGELOG.md
index f563d45a0..886e386d4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@ Thank you!
 
 # 0.18.25
 
+* Fixes a regression from 0.18.4 which incorrectly rendered default values for certain types (see [#1593](https://github.com/disneystreaming/smithy4s/pull/1593))
 * Fixes an issue in which union members targetting Unit would fail to compile when used as traits (see [#1600](https://github.com/disneystreaming/smithy4s/pull/1600)).
 * Make the `transform` method in generated `*Gen` algebras final. This should make it possible to derive e.g. `FunctorK` instances in cats-tagless automatically (see [#1588](https://github.com/disneystreaming/smithy4s/pull/1588)).
 
diff --git a/modules/bootstrapped/src/generated/smithy4s/example/DefaultNotCapitalized.scala b/modules/bootstrapped/src/generated/smithy4s/example/DefaultNotCapitalized.scala
new file mode 100644
index 000000000..eb201f159
--- /dev/null
+++ b/modules/bootstrapped/src/generated/smithy4s/example/DefaultNotCapitalized.scala
@@ -0,0 +1,22 @@
+package smithy4s.example
+
+import smithy4s.Hints
+import smithy4s.Schema
+import smithy4s.ShapeId
+import smithy4s.ShapeTag
+import smithy4s.schema.Schema.struct
+
+final case class DefaultNotCapitalized(name: Username = smithy4s.example.Username("hello"))
+
+object DefaultNotCapitalized extends ShapeTag.Companion[DefaultNotCapitalized] {
+  val id: ShapeId = ShapeId("smithy4s.example", "DefaultNotCapitalized")
+
+  val hints: Hints = Hints.empty
+
+  // constructor using the original order from the spec
+  private def make(name: Username): DefaultNotCapitalized = DefaultNotCapitalized(name)
+
+  implicit val schema: Schema[DefaultNotCapitalized] = struct(
+    Username.schema.required[DefaultNotCapitalized]("name", _.name).addHints(smithy.api.Default(smithy4s.Document.fromString("hello"))),
+  )(make).withId(id).addHints(hints)
+}
diff --git a/modules/bootstrapped/src/generated/smithy4s/example/Username.scala b/modules/bootstrapped/src/generated/smithy4s/example/Username.scala
new file mode 100644
index 000000000..9c7fab14b
--- /dev/null
+++ b/modules/bootstrapped/src/generated/smithy4s/example/Username.scala
@@ -0,0 +1,15 @@
+package smithy4s.example
+
+import smithy4s.Hints
+import smithy4s.Newtype
+import smithy4s.Schema
+import smithy4s.ShapeId
+import smithy4s.schema.Schema.bijection
+import smithy4s.schema.Schema.string
+
+object Username extends Newtype[String] {
+  val id: ShapeId = ShapeId("smithy4s.example", "username")
+  val hints: Hints = Hints.empty
+  val underlyingSchema: Schema[String] = string.withId(id).addHints(hints)
+  implicit val schema: Schema[Username] = bijection(underlyingSchema, asBijection)
+}
diff --git a/modules/bootstrapped/src/generated/smithy4s/example/package.scala b/modules/bootstrapped/src/generated/smithy4s/example/package.scala
index 568c337a0..b36f14d6a 100644
--- a/modules/bootstrapped/src/generated/smithy4s/example/package.scala
+++ b/modules/bootstrapped/src/generated/smithy4s/example/package.scala
@@ -118,6 +118,7 @@ package object example {
   type UVIndex = smithy4s.example.UVIndex.Type
   type UnicodeRegexString = smithy4s.example.UnicodeRegexString.Type
   type UnwrappedFancyList = smithy4s.example.UnwrappedFancyList.Type
+  type Username = smithy4s.example.Username.Type
   type ValidatedString = smithy4s.example.ValidatedString.Type
 
 }
\ No newline at end of file
diff --git a/modules/codegen/src/smithy4s/codegen/internals/CollisionAvoidance.scala b/modules/codegen/src/smithy4s/codegen/internals/CollisionAvoidance.scala
index ac0d50ac0..f6b6e2f87 100644
--- a/modules/codegen/src/smithy4s/codegen/internals/CollisionAvoidance.scala
+++ b/modules/codegen/src/smithy4s/codegen/internals/CollisionAvoidance.scala
@@ -154,15 +154,28 @@ private[internals] object CollisionAvoidance {
 
   private def modField(field: Field): Field = {
     Field(
-      protectKeyword(uncapitalise(field.name)),
-      field.name,
-      modType(field.tpe),
-      field.modifier,
-      field.originalIndex,
-      field.hints.map(modHint)
+      name = protectKeyword(uncapitalise(field.name)),
+      realName = field.name,
+      tpe = modType(field.tpe),
+      modifier = modModifier(field.modifier),
+      originalIndex = field.originalIndex,
+      hints = field.hints.map(modHint)
     )
   }
 
+  private def modModifier(modifier: Field.Modifier): Field.Modifier =
+    Field.Modifier(
+      required = modifier.required,
+      nullable = modifier.nullable,
+      default = modifier.default.map(modFieldDefault)
+    )
+
+  private def modFieldDefault(default: Field.Default): Field.Default =
+    Field.Default(
+      node = default.node,
+      typedNode = default.typedNode.map(recursion.preprocess(modTypedNode))
+    )
+
   private def modStreamingField(
       streamingField: StreamingField
   ): StreamingField = {
diff --git a/sampleSpecs/defaults.smithy b/sampleSpecs/defaults.smithy
index 9615d02ef..868024331 100644
--- a/sampleSpecs/defaults.smithy
+++ b/sampleSpecs/defaults.smithy
@@ -72,3 +72,11 @@ structure DefaultVariants {
 }
 
 structure DefaultInMixinUsageTest with [DefaultInMixinTest] {}
+
+// Regression test for https://github.com/disneystreaming/smithy4s/issues/1592
+structure DefaultNotCapitalized {
+    @required
+    name: username = "hello"
+}
+
+string username