Guests leaving bad cleanliness reviews when the place is clean

Firstly don’t panic! I’ve been sitting on 4.6 for Cleanliness for several years and as I have 5s on everything else I am still a SH and no shortage of bookings. Even over the last couple of years I’d be a 4.8. Some people will just give you a 4 for cleanliness because cleanliness is their thang. I’ve even had guests who love the place, rebook, and on leaving tell me they’ve given it a “really good clean”. I thank them profusely. I also ask a friend of mine who used to work as hotel housekeeper to come in and give me the full “hotel Inspector” review. Amazing stuff some people notice.