It would not be OK for me. Whether or not there is a client session beforehand, it reflects an inability to properly manage the frame of therapy, so it's a problem that I think isn't only about time management. I guess if I liked the therapist otherwise, I would bring it up, express my feelings about it, and ask for a direct response about whether the behavior was likely to continue. If so, I'd have to either become OK with it, or leave.
I doubt that it has anything to do with any feelings the therapist has about you personally, but it's understandable that it would make you wonder about that--one of the reasons such behavior isn't just about time.