Yeah I experienced that too, even after a two weeks intensive therapy. I think in real-life situations we tend to want to speak more naturally and the social and temporal stress is way higher compared to a therapy setting. What you could do is really concentrating on your techniques, slowing down even more than you‘d like until these new patterns are really hammered into your brain. But in my experience, this is just really difficult to achieve, as my live consists of more than constantly practicing and learning to speak fluently. The unnaturalness of these ways of speaking only makes it harder. I think of stuttering as a result of a very fragile speech planning and execution system. If any kind of stressors (and therefore more input to integrate) are added, be it social, temporal or otherwise, the system falls apart and the speech coordination is off.