Last year, I had something similar for my PM role hiring. After the rounds communicated were done, HRs went silent. After a week they scheduled a new VP level round.
Now after joining, my personal experience is that additional rounds do get scheduled if the initial group of interviewers have not been able to come to a solid Yes. Some of them would have given a Yes but atleast one interviewer would have been indecisive. The additional rounds would be around the doubts this indecisive interviewer would have raised.
The only reason to circle back to you would be that they might not have found any other suitable candidate and therefore you might have a good chance of getting through.