diff --git a/main/src/main/scala/sbt/Defaults.scala b/main/src/main/scala/sbt/Defaults.scala
index 9553e3b65..2073f6feb 100644
--- a/main/src/main/scala/sbt/Defaults.scala
+++ b/main/src/main/scala/sbt/Defaults.scala
@@ -3134,17 +3134,16 @@ object Classpaths {
       }).value),
     csrSameVersions ++= {
       partialVersion(scalaVersion.value) match {
-        // See https://github.com/sbt/sbt/issues/8224
-        // Scala 3.8+ should align only Scala3_8Artifacts
-        case Some((3, minor)) if minor >= 8 =>
-          ScalaArtifacts.Scala3_8Artifacts
-            .map(a => InclExclRule(scalaOrganization.value, a))
-            .toSet :: Nil
-        case Some((major, minor)) if major == 2 || major == 3 =>
+        case Some((major, minor)) if major == 2 && minor < 13 =>
           ScalaArtifacts.Artifacts
             .map(a => InclExclRule(scalaOrganization.value, a))
             .toSet :: Nil
-        case _ => Nil
+        // Due to the Scala 2.13-3.x sandwich, the absence of scala-reflect
+        // that corresponds with scala-library 3.8.x propagates to 2.13 builds as well.
+        case _ =>
+          ScalaArtifacts.Scala3_8Artifacts
+            .map(a => InclExclRule(scalaOrganization.value, a))
+            .toSet :: Nil
       }
     },
     moduleName := normalizedName.value,
diff --git a/sbt-app/src/sbt-test/dependency-management/stdlib-3.8/build.sbt b/sbt-app/src/sbt-test/dependency-management/stdlib-3.8/build.sbt
new file mode 100644
index 000000000..58ef2f92f
--- /dev/null
+++ b/sbt-app/src/sbt-test/dependency-management/stdlib-3.8/build.sbt
@@ -0,0 +1,12 @@
+lazy val a = project
+  .settings(
+    scalaVersion := "3.8.1"
+  )
+
+// (b / update) sbt.librarymanagement.ResolveException: Error downloading org.scala-lang:scala-reflect:3.8.1
+lazy val b = project
+  .dependsOn(a)
+  .settings(
+    scalaVersion := "2.13.10",
+    libraryDependencies += "org.scala-lang" % "scala-reflect" % "2.13.10",
+  )
diff --git a/sbt-app/src/sbt-test/dependency-management/stdlib-3.8/test b/sbt-app/src/sbt-test/dependency-management/stdlib-3.8/test
new file mode 100644
index 000000000..103bd8d2f
--- /dev/null
+++ b/sbt-app/src/sbt-test/dependency-management/stdlib-3.8/test
@@ -0,0 +1 @@
+> update
diff --git a/sbt-app/src/sbt-test/dependency-management/stdlib-unfreeze/build.sbt b/sbt-app/src/sbt-test/dependency-management/stdlib-unfreeze/build.sbt
index ab04ff427..6d4696357 100644
--- a/sbt-app/src/sbt-test/dependency-management/stdlib-unfreeze/build.sbt
+++ b/sbt-app/src/sbt-test/dependency-management/stdlib-unfreeze/build.sbt
@@ -3,12 +3,12 @@ import sbt.librarymanagement.InclExclRule
 lazy val a = project.settings(
   scalaVersion := "2.13.11",
   libraryDependencies += "org.scala-lang" % "scala-reflect" % scalaVersion.value,
-  TaskKey[Unit]("checkLibs") := checkLibs("2.13.11", (Compile/dependencyClasspath).value, ".*scala-(library|reflect).*"),
+  TaskKey[Unit]("checkLibs") := checkLibs("2.13.11", (Compile/dependencyClasspath).value, ".*scala-library.*"),
 )
 
 lazy val b = project.dependsOn(a).settings(
   scalaVersion := "2.13.12",
-  TaskKey[Unit]("checkLibs") := checkLibs("2.13.12", (Compile/dependencyClasspath).value, ".*scala-(library|reflect).*"),
+  TaskKey[Unit]("checkLibs") := checkLibs("2.13.12", (Compile/dependencyClasspath).value, ".*scala-library.*"),
 )
 
 lazy val a3 = project.settings(
diff --git a/sbt-app/src/sbt-test/dependency-management/stdlib-unfreeze/test b/sbt-app/src/sbt-test/dependency-management/stdlib-unfreeze/test
index 8eb173463..2504dd508 100644
--- a/sbt-app/src/sbt-test/dependency-management/stdlib-unfreeze/test
+++ b/sbt-app/src/sbt-test/dependency-management/stdlib-unfreeze/test
@@ -15,6 +15,5 @@ $ delete s2.13.14.txt
 # without the default `csrSameVersions`, scala-reflect in b stays at 2.13.11
 > set b/csrSameVersions := Nil
 > b/update
--> b/checkLibs
 
 > ak/checkLibs