Hi @anon19843511, welcome to the Asana Community Forum!
In order to investigate this further, I recommend you to contact our support team and provide this information:
- URL of the task that shouldn’t appear in your list when sorting by Last Modified
- URL of this thread so you don’t need to re-write everything
Unfortunately I don’t have the tools in the forum to have a closer look and investigate this issue but our support team can certainly help you solve it!
Let me know if I can help you with anything else. Have a great day!