Sometimes there are websites where click on the flag of the required translation language unexpectedly moves a visitor, for example, to the main page, or leaves him on the current one. Probably the necessary page is missing, and the web-designer simply did not take care to notify about it. Modern Joomla has extensive capabilities to support multilingualism in such cases, but there is a nuances.
Note: do not forget to forcefully scan Categories and Menus after the update (click the button Build). From my own very old negative experience, I assume that this button was added because Joomla! stores important settings in JSON structures of Database fields of the type 'mediumtext'.
If you leave this field blank, the duplicates in the ScreamingFrog report will go to the Missing Meta Keywords list, which is still better.
I hope the above material will be useful to you.