It also likely that you have conveniently forgotten these incidents because they did not strike you as particularly noteworthy at the time. Or, your daughter may have misremembered details about when the events happened. That doesn’t mean she wasn’t abused in ways similar to what she describes. Be careful that your motivations do not skew your interpretation of this tough situation — the fact that you’re using her seemingly inaccurate memory as a reason to call her relationship with her therapist into question is worrisome. You two will need to work out this conflict with the help of a mediator — a counselor sitting in on these conversations is a very, very good idea. That’s if your daughter is comfortable being with you and discussing it at all.
False memories can be implanted, but they require a lot of intentional work and practice. Aside from the psychologists who implanted some of the satanic ritual false memories in the 1980’s, there are very few documented incidents of a therapist doing something like that. Contrast that with cops and investigators; the nature of their questioning practices is much more conducive to implanting false memories. The fact that your reaction to being accused of abuse is to doubt that the event happened at all is very worrisome. It is painful to acknowledge we might have done harm. But for the sake of your relationship with your daughter it is essential that you do so.