I think that when you grab for her, it's a fast motion that may look like play. You might want to do "collar grabbing" practice with her, when you are relaxed. Grab her collar while you're petting her in your lap. Grab her collar and give her a treat, then give her supper... and so on, so that she learns not to react to a collar grab.
Also, teach her to come running downstairs by shaking her treat bag, calling her, and giving her a treat ... repeating many times throughout the day. After she's reliable for 3 days, don't shake the treat bag, just call and treat.
If she is already fixed, then I don't believe that there are any biological changes that should happen that would result in accidents from a 7.5 mo pup.
Also, teach her to come running downstairs by shaking her treat bag, calling her, and giving her a treat ... repeating many times throughout the day. After she's reliable for 3 days, don't shake the treat bag, just call and treat.
If she is already fixed, then I don't believe that there are any biological changes that should happen that would result in accidents from a 7.5 mo pup.