Fix executeTask for new'd tasks

Fixes #145065

src/vs/workbench/contrib/tasks/browser/abstractTaskService.ts

@@ -1700,7 +1700,10 @@ export abstract class AbstractTaskService extends Disposable implements ITaskSer
 			const taskFolder = task.getWorkspaceFolder();
 			const taskIdentifier = task.configurationProperties.identifier;
 			// Since we save before running tasks, the task may have changed as part of the save.
-			taskToRun = ((taskFolder && taskIdentifier) ? await this.getTask(taskFolder, taskIdentifier) : task) ?? task;
+			// However, if the TaskRunSource is not User, then we shouldn't try to fetch the task again
+			// since this can cause a new'd task to get overwritten with a provided task.
+			taskToRun = ((taskFolder && taskIdentifier && (runSource === TaskRunSource.User))
+				? await this.getTask(taskFolder, taskIdentifier) : task) ?? task;
 		}
 		await ProblemMatcherRegistry.onReady();
 		let executeResult = this.getTaskSystem().run(taskToRun, resolver);