The elements of your page have been translated with the "translate" method instead of "copy".
This disallows the reorder of the translated elements; I don't know if it is a default setting of the upgrade process.
To change the status of the elements from "translate" and make them "copies" you have to clear the field "Transl.Orig." of each content element on the page.
This operation is fundamental,as in TYPO3 version 7.6+, the behavior of translations has been streamlined, and now it is no more possible to "mix" on the same page elements which are a translation of the original element and elements which are a copy. (this was tolerated until 6.2 but currently it is not, and TYPO3 warns you that you have an inconsistent situation on your page).
It is also possible to bring back the previous behavior via the TSConfig:
mod.web_layout.allowInconsistentLanguageHandling = 1