diff --git a/core/shared/src/main/scala/coursier/maven/MavenSource.scala b/core/shared/src/main/scala/coursier/maven/MavenSource.scala
index ac4e9133b..20c64dad0 100644
--- a/core/shared/src/main/scala/coursier/maven/MavenSource.scala
+++ b/core/shared/src/main/scala/coursier/maven/MavenSource.scala
@@ -281,7 +281,7 @@ final case class MavenSource(
               k -> other.extra.get(k).fold(v)(merge(v, _))
           } ++
           other.extra
-            .filterKeys(k => !a.extra.contains(k))
+            .filterKeys(k => !a.extra.contains(k) && k != Artifact.optionalKey)
 
         a.copy(
           checksumUrls = other.checksumUrls ++ a.checksumUrls,
diff --git a/tests/metadata b/tests/metadata
index ac3871c92..93eccec4f 160000
--- a/tests/metadata
+++ b/tests/metadata
@@ -1 +1 @@
-Subproject commit ac3871c925e035157203d6d799a9a2c7c2578d67
+Subproject commit 93eccec4ffd1719586b6f1e1dddefcbea6722e7d
diff --git a/tests/shared/src/test/scala/coursier/test/CentralTests.scala b/tests/shared/src/test/scala/coursier/test/CentralTests.scala
index 281b60907..bf91d54ea 100644
--- a/tests/shared/src/test/scala/coursier/test/CentralTests.scala
+++ b/tests/shared/src/test/scala/coursier/test/CentralTests.scala
@@ -804,6 +804,23 @@ abstract class CentralTests extends TestSuite {
         val mainArtifactOpt = artifacts.find(_.url == mainUrl)
         assert(mainArtifactOpt.isEmpty)
       }
+
+      * - {
+        if (isActualCentral)
+          withArtifacts(Module("com.lihaoyi", "scalatags_2.12"), "0.6.2", "jar", transitive = true, optional = false) { artifacts =>
+
+            assert(artifacts.forall(!_.isOptional))
+
+            val urls = artifacts.map(_.url).toSet
+
+            val expectedUrls = Set(
+              "https://repo1.maven.org/maven2/org/scala-lang/scala-library/2.12.0/scala-library-2.12.0.jar",
+              "https://repo1.maven.org/maven2/com/lihaoyi/sourcecode_2.12/0.1.3/sourcecode_2.12-0.1.3.jar",
+              "https://repo1.maven.org/maven2/com/lihaoyi/scalatags_2.12/0.6.2/scalatags_2.12-0.6.2.jar"
+            )
+            assert(urls == expectedUrls)
+          }
+      }
     }
   }