Sometimes people aren't lying (and why would she do so to a colleague?) but are mistaken. I could see how something you would have said as a prospective client ("before the first session") might not make it into her memory; because therapy doesn't really start until the first session and T's likely talk to many people as prospectives who don't show up, so the memory thing isn't engaged the way it is when someone is in front of you. Or maybe she came to think that because you didn't deal with your addiction much in those early times in therapy.

I could also see how your memory could be mistaken, in the sense that maybe you intended to say it but was caught up and didn't.

I think her clinical notes would reveal what she thought she knew at the time. There could be many reasons why her impression of what you'd revealed is different than what you remember you said. I think this happens all the time and memory can shift from the integration of new information. Maybe she didn't realize how bad your addiction was and that reframed what she thought she knew and when.

This is probably one of the risks of having current T's consult with former ones. My guess is that the former ones get a lot of stuff wrong. I imagine your current T is used to dealing with this phenomenon or at the least is familiar with the basic psych principle that 2 people having the same conversation can come away with vastly different ideas of what's been said.

Sometimes it has helped me to try to find the more benign explanation such as mistake rather than go full on hostile and accuse someone of more than the facts can indicate.