Pre-heat the pressure cooker using the BROWN setting.
Add the olive oil, season the short ribs with salt and pepper and sear them in batches, until browned on all sides – about 15 minutes. Once the ribs are nicely browned, remove them to a side plate and set aside. Pour off and discard the fat that has accumulated in the cooker. Add the onion and celery and cook for 2 to 3 minutes. Add the garlic, thyme, and bay leaf and continue to cook for another minute.
Add the wine and deglaze the cooker, scraping up any brown bits on the bottom of the pot. Let the wine simmer and reduce until it has almost entirely disappeared. Add the orange juice and soy sauce and return the browned short ribs to the cooker. Lock the lid in place.
Pressure cook on HIGH for 45 minutes.
Let the pressure drop NATURALLY and carefully remove the lid. Remove the ribs from the cooker and set aside, loosely covered with foil. Using the BROWN setting on the pressure cooker, simmer the braising liquid until it has thickened slightly and is almost syrupy like a glaze. Return the ribs to the cooker and turn them to coat in this sauce.