Problem:
In each translation there is a field called "field-_elementor_data" inside "Custom Fields" and I don't know how to delete it.
Solution:
Please try the following steps to remove the custom field from the translation editor:
1. Go to WPML > Settings > Custom Fields Translation
2. Click the "Show System Fields" link
3. Search for the field
4. Set it to "Copy Once" and save the changes
This will be applied to all the new translations. For the existing translations, please try the following steps to apply the above changes:
1. Edit the original page/post
2. Make a small change and update the page
3. Update the translation