If you ever see this, it means Threads picked the post for you. It can be unclear and appear that the “pick” may appear to have been done by the person shown in the notifications.
Rest assured, it’s just a vague message from Threads, suggesting the post to you. Good User Interface (U.I.) would suggest they should use familiar language “Suggested for you” or more clear language “Threads picked for you.”
Hopefully this clears it up for you better than Threads did!