I wouldn’t be sure but I believe stuttering in a way can sometimes kinda be like a dissociative disorder. Sometimes your brain might try to block out the current moment because it emotionally doesn’t feel like something you can identify with. This can cause blocking due to your brain wanting to shut down your speaking to avoid social mistakes or otherwise speaking outside of what you believe your social role is. Or on the flip side the disassociating could actually cause fluency because you stop being affected by those uncomfortable emotions (you become numb) in the speaking situation. Or you’re flipping back and forth between dissociation and feeling your emotions, which causes fluency due to your emotions and speech production mechanisms being in harmony. I think either can happen. Could be wrong but it’s just food for thought that you might want to work on generally being more accepting of the moment so that your brain doesn’t use dissociation as a defense mechanism. Better off feeling your emotions and embracing them when you know logically that it’s safe to do so. Hope this makes sense.