Idk what the formal clinical definition of a stutter is but that is definitely a common issue amongst stutters. Blocks have gotta be one of the most annoying parts as you feel helpless trying to say something and your mouth/ throat gets all tense and won’t push out the word. Plus your face is all strange trying to say the word. On a positive note though I try to reduce blocking my paying attention to my breathing before starting a sentence. That is I take a slightly larger breath before a sentence so when I start to speak the words roll off of the exhale which helps push the words out. It’s kinda odd at first and can be awkward but you can get into a rhythm which can help.