Ideas
I ran through some testing on this after some reports were brought up in a Discord support server. I can confirm both veterinary clinics and retail lots from GTW are non-functional, and restaurants are unaffected.
My save is completely vanilla and I removed my resource.cfg file for good measure before launching the game and creating the new save for testing purposes. I tested Brindleton Pawspitle for the vet clinic, and all three retail lots in Magnolia Promenade. At no point did any staff OR NPC customers spawn in. I spent time there and waited to see if this would change, but it did not. The most I was able to do was buy an outfit off a mannequin in one of the shops since this did not require an employee to work. However, all other items listed for sale in the store had no interaction popups when I clicked items available for sale.
I do have a copy of this save I can provide if needed at all. I do own all available game content released to date (and have pre-ordered Buisnesses & Hobbies).