Duplicating Records When Inserting

PG Doc comments form <[email protected]> Sat, 26 Oct 2019 17:48:33 +0000
Newsgroups gmane.comp.db.postgresql.devel.documentation
Message-ID <[email protected]>
The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/11/release-11-5.html
Description:

Hello, when starting to use postgres version 11.5, there are duplicate
records, what can it be?
I have always used 9.6 and never had this problem.
I'm confused, is there anything you can do?
Thank you so much for your attention!