Sentence revisions, like repetitions, are normal, they occur in everybody’s speech. However, if that happens too often the communication gets disturbed. In cluttering, sentence revisions are common.
For example: ”I cycled, uh … I walked home.” Or: “Then we went back to New Y … um, oh no, we went to Boston first and had a cup of coffee there… no, we shopped. I think. Hmm… maybe it was the other way around”.
Like repetitions, sentence revisions are symptoms of syntactic cluttering.