Hello, while using STELA notifications for pending offers remains active, even if you've seen the offer, approved or declined already.
it is always on unless you delete the ad.

How can I fix it?

It's not checking if it was read or not, just showing if there are offers or not.
You can find it in functions.php

  if(function_exists('mo_show_offer_link')) {
    $your_items = ModelMO::newInstance()->getItemsWithOffersByUserId(osc_logged_user_id());
   .....