Ok, I think I know what happens. You need pins uploaded for the 2nd language. Same for the 3rd language. And so on. It’s because the custom taxonomies translated have new IDs when translated with WPML, and wordpress needs to have a pin for each category/id.
Go to theme options – Pin management. Select the 2nd language from the drop-down. And upload pins for that language. save.
If you need my help, send me wp-admin and I will give a hand.