We just encountered this issue today. SP21 was installed less than a week ago and released some code less than 24 hours ago. Publish was fine for some time and suddenly start throwing errors. Issue did not occur across all Publish instance consistently, only 1 of the Publish instance was encounterin...

I've managed to get this working by updating 2 locations:1) /apps/wcm/core/resources/languages/in_id2) /apps/<projectname>/i18n/idFor (1), I did not need to add a "defaultCountry" property to the node to get it working. This step will add "Indonesian" into the languages dropdown in page propertiesFo...