Hello @Los6565,
My Tasks is not a project per se, it is your place where you gather all tasks assinged to you. When you add task to another project (one or more), Asana will show it inside this project (projects) but this is not duplicated tasks - it is the same task (multihoming tasks - Connecting Your Work Across Asana | Product Guide • Asana Product Guide).
What do you want to accomplish by adding it to another project?
If you want to remove it from My Task, you have to unassinged it from you.