Interesting thing about my stuttering

Interesting thing about my stuttering I have a pretty severe stuttering (if I talk face to face or on the phone - I mean most of my speech is fluent but I have very severe blocks especially at the beginning of my sentences) but when I make a video about myself or talk on Viber (which is not real-time communication) I can speak almost fluently. Have any of you experienced a similar phenomenon? (And language therapists couldn't help me in the past because I spoke fluently as long as I was in their offices. One of them accused me jokingly that I'm not even stuttering but only imitate it, which I find funny).