Is this the post you're talking about? https://www.stutteringtreatment.org/blog/can-a-block-be-an-avoidance-behavior  The information in it is good and the SLP is known in the community, although I'd argue most prolongation a are probably also avoidance.  I also know it's an avoidance behavior because it's a behavior I used to do a lot and have largely gotten rid of it through intentional practice. I know many others who have similarly worked to reduce their blocking behaviors.  If youd like to read more, look up the approach-avoidance conflict by Sheehan.