This is a common practice with some patent drafters. It resulted from some judges taking “the summary of the invention” section as limiting the claims. A few years ago the term patent profanity was coined. It is about words you should not use in the description for fear they will be taken by a judge to override the words of the claims,
“Invention” is the biggest patent profanity. “The invention uses a spring” in the description is taken to implicitly add the word spring to every claim. You might have meant some embodiments use something that has spring-like properties, depending on your careful claim wording to define your rights but a judge reads “has a “spring” into every claim because of your use of “invention”.
This is particularly worrying in the summary. So some people recommend that the summary basically just repeat the claims so there is no room to use the summary wording to misconstrue the claims. Others advocate not including a summary at all.
Reiterating claims elsewhere is not as common. One motivation is the fact that the disclosure, as filed, must support the ultimate claims and people do not appreciate that initially present claims are part of the disclosure.