Urgent: ES checkbox fields disappear

Hello SI Support, we have some custom fields with checkboxes in User Workflow. Now in two fields some checkbox values are disappeared. Can you imagine why this can happen? What Database is holding these fields and values, where could i take a look, if values are still existing or if they have gone. Any Idea?

Unfortunately this is a private intranet, so i can't give you a public url to take a look.

Thank you and best regards