At first I thought yes, lying, but Allheart makes a great point. She might have had you and the other client switched around on her schedule, so you were on her schedule for 11 and her 11 was on her schedule for 10. She might have thought her scheduled 10 was late until you texted and then realized her error. If you otherwise trust her, I would go with this version until you can find out from her why she said that.