diff --git a/src/main/java/net/fabricmc/loom/configuration/CompileConfiguration.java b/src/main/java/net/fabricmc/loom/configuration/CompileConfiguration.java
index 8bd3ea4e..aa87a06e 100644
--- a/src/main/java/net/fabricmc/loom/configuration/CompileConfiguration.java
+++ b/src/main/java/net/fabricmc/loom/configuration/CompileConfiguration.java
@@ -59,6 +59,7 @@ import org.gradle.api.logging.Logger;
 import org.gradle.api.logging.Logging;
 import org.gradle.api.plugins.JavaPlugin;
 import org.gradle.api.plugins.JavaPluginExtension;
+import org.gradle.api.provider.Provider;
 import org.gradle.api.tasks.AbstractCopyTask;
 import org.gradle.api.tasks.SourceSet;
 import org.gradle.api.tasks.TaskContainer;
@@ -368,7 +369,10 @@ public abstract class CompileConfiguration implements Runnable {
 		}
 
 		getProject().getTasks().named(JavaPlugin.TEST_TASK_NAME, Test.class, test -> {
-			test.getInputs().property("LoomClassPathGroups", ClasspathGroupService.create(getProject()));
+			Provider<ClasspathGroupService.Options> optionsProvider = ClasspathGroupService.create(getProject());
+			test.getInputs().property("LoomClassPathGroups", optionsProvider);
+			test.getInputs().files(optionsProvider.map((ClasspathGroupService.Options::getExternalClasspathGroups)));
+
 			test.doFirst(new Action<Task>() {
 				@Override
 				public void execute(Task task) {
diff --git a/src/main/java/net/fabricmc/loom/task/LoomTasks.java b/src/main/java/net/fabricmc/loom/task/LoomTasks.java
index 312d558d..94778cf8 100644
--- a/src/main/java/net/fabricmc/loom/task/LoomTasks.java
+++ b/src/main/java/net/fabricmc/loom/task/LoomTasks.java
@@ -237,9 +237,9 @@ public abstract class LoomTasks implements Runnable {
 			task.setGroup(Constants.TaskGroup.FABRIC);
 
 			if (operatingSystem.isWindows()) {
-				task.from(getProject().zipTree(downloadRenderDoc.map(DownloadTask::getOutput)));
+				task.from(getProject().zipTree(downloadRenderDoc.flatMap(DownloadTask::getOutput)));
 			} else {
-				task.from(getProject().tarTree(downloadRenderDoc.map(DownloadTask::getOutput)));
+				task.from(getProject().tarTree(downloadRenderDoc.flatMap(DownloadTask::getOutput)));
 			}
 
 			task.into(getProject().getLayout().getBuildDirectory().dir("renderdoc"));