is it legally valid 4 a prop mgr 2 prepare a lease 4 tenants & @ signing lv rm to copy lease & return w/ sig from unknown party?

During the signing of our lease, the prop. mgr., who's full name was listed on each pg as the preparer of said lease/doc., left the room to make copies of the lease for our records. The receptionist for the co. returned w/ our copy and we were told that was it. We reached the prkng lot and I noticed that the last pg of the lease was signed by someone that was not present during signing and who's name was never even mentioned. The office had closed that fast and when I called the prop mgr on her cell to question the sig. She states it was standard. I requested a signed copy w/ our prop mgr's sig (same as preparer) and was told it wasn't necessary. We love the house & like the owner but can't stand the prop mgr. Now what?