CreateTask uses the JobScheduler API of Android, which has a maximum life span of ~15 minutes. This is used for non-critical tasks such as uploading logs or debug information to a server.
For a user-visible task, use CreateProcess, and there won't be a permanent notification on Android 15+ devices.
Then, in the procedure, use a clock component, set its interval, listen to the Clock's Timer event, and create and post a notification there.
Refer to the "Doing a GET request every 5 seconds" in the topic's guide:
In the bgTimer, replace the Web blocks with your Melon Notification blocks.