Make sure you've got included SSTC box ticked
Just looked myself and you're right it's gone
🫣 very strange for an estate agent to do that, I'm on Rightmove all the time and typically it will sit as under offer or SSTC for a few months while the sale is going through, I've even seen in some cases it still being on rightmove a couple of weeks after where the new owner has moved in! Obviously a buyer could pull out at any point during the sale process for many reasons like unfavourable survey results, chain collapses, change of heart, so obvs it's easier to keep the ad on Rightmove then change it back to for sale than deleting completely.
Very strange indeed.