Steps to reproduce the issue

Go to the new mail templates components found on the system page
Set the number of items to display at anything less than the total number of items eg 5
open the filter options
click on the select component filter to see the options

Expected result

All the text is translated strings ie "USERS" not "com_users"

Actual result

ONLY the text for items on the current page is translated
When you change page or apply a filter then once again only the text for the items on that page is translated

Comment

It is as if the *.sys.ini files are not loaded but language debug says they are

Demo