diff --git a/lm-core/src/main/scala/sbt/librarymanagement/CrossVersionExtra.scala b/lm-core/src/main/scala/sbt/librarymanagement/CrossVersionExtra.scala
index 45a67d52a..aafc4a1c2 100644
--- a/lm-core/src/main/scala/sbt/librarymanagement/CrossVersionExtra.scala
+++ b/lm-core/src/main/scala/sbt/librarymanagement/CrossVersionExtra.scala
@@ -168,17 +168,17 @@ private[librarymanagement] abstract class CrossVersionFunctions {
 
   /**
    * Appends the platform suffix (e.g. `native0.5`, `sjs1`) to `name`, preferring an explicit
-   * `platformOpt` over the `projectPlatform`. `""` and `jvm` add no suffix.
+   * `platformOpt` over the `projectPlatform`. `""` and `jvm` add no suffix. Keep in sync with
+   * `lmcoursier.FromSbt.addPlatformSuffix` (until lm-coursier moves under sbt).
    */
-  def addPlatformSuffix(
+  private[sbt] def addPlatformSuffix(
       name: String,
       platformOpt: Option[String],
       projectPlatform: Option[String]
   ): String =
-    (platformOpt orElse projectPlatform) match {
+    platformOpt.orElse(projectPlatform) match
       case Some(p) if p.nonEmpty && p != Platform.jvm => crossName(name, p)
       case _                                          => name
-    }
 
   /** Cross-versions `exclude` according to its `crossVersion`. */
   private[sbt] def substituteCross(
diff --git a/lm-coursier/src/main/scala/lmcoursier/FromSbt.scala b/lm-coursier/src/main/scala/lmcoursier/FromSbt.scala
index b02f4c3ad..0516dcd32 100644
--- a/lm-coursier/src/main/scala/lmcoursier/FromSbt.scala
+++ b/lm-coursier/src/main/scala/lmcoursier/FromSbt.scala
@@ -32,7 +32,7 @@ object FromSbt {
     val name1 =
       crossVersion match
         case _: Disabled => name0
-        case _           => CrossVersion.addPlatformSuffix(name0, platformOpt, projectPlatform)
+        case _           => addPlatformSuffix(name0, platformOpt, projectPlatform)
     val updatedName = CrossVersion(crossVersion, scalaVersion, scalaBinaryVersion)
       .fold(name1)(_(name1))
     if (!optionalCrossVer || updatedName.length <= name0.length)
@@ -46,6 +46,27 @@ object FromSbt {
     }
   }
 
+  // Duplicate of sbt.librarymanagement.CrossVersion.addPlatformSuffix. Keep the two in sync
+  // until lm-coursier moves under sbt
+  private def addPlatformSuffix(
+      name: String,
+      platformOpt: Option[String],
+      projectPlatform: Option[String]
+  ): String = {
+    def addSuffix(platformName: String): String =
+      platformName match {
+        case "" | "jvm" => name
+        case _          => s"${name}_$platformName"
+      }
+    (platformOpt, projectPlatform) match {
+      case (Some(p), _) =>
+        addSuffix(p) // Use explicit platform if set (don't override with project platform)
+      case (None, Some(p)) =>
+        addSuffix(p) // Only use project platform if dependency has no explicit platform
+      case _ => name
+    }
+  }
+
   private def attributes(attr: Map[String, String]): Map[String, String] =
     attr
       .map { (k, v) =>