Since the rest of the paper looks decent (I am no expert in this field), I have a guess: it got to review and it came back with a ‘minor review’ and the comment ‘please summarize XY at the end’.

In low impact journals minor reviews are handeled in a way, that the editor trusts the scientists to address minor changes accordingly. Afterwards it goes to production, where some badly payed people – most of the time from India – put everything in format, send out a proof with a deadline of max 2 days and then it will be published.

I don’t want to defend this practice, but thats how something like this can get through.