The theme has a language translation template /languages/trusted.pot which contains all the translatable strings – ‘Recent’ is one of these strings so it can be translated into any language.
But if you change the default ‘Recent’ to ‘Our latest additions’ then the translation plugin won’t automatically translate ‘Our latest additions’ to ‘Laatst toegevoegd’ because it cannot find ‘Our latest additions’.
It can only know to translate ‘Recent’ so the new string ‘Our latest additions’ needs to be added as a translatable string.
This can be done either by creating your own language template containing the string ‘Our latest additions’ or by adding the key value tab_label_recent as that is the key of the new value in the database, so WPML will know to translate whatever the value of tab_label_recent is into a different language.
Go to ‘WPML’ > ‘String Translation’
click ‘Translate texts in admin screens’
look down the list for ‘+ theme_mods_trusted-pro’ click it to open
look for key name ‘tab_label_recent’ and check the box next to it
(plus any others you may want to translate)
click ‘Apply’
you should see message “The selected strings can now be translated using the string translation screen”
go back to the String translation screen and you should see the newly added string ready to be translated