@ytez Based on the original post. Checkboxes can be added in several manners, so I believe Nathaly was inquiring as to how they were added. For example, when you click and move a Checkbox onto a document you can then click that checkbox and add more checkboxes to the Checkbox Group. Some individuals will take a checkbox and then grab another checkbox from the field selection in essence creating several checkbox groups instead of two checkboxes within one checkbox group.
Overall, if you set a validation of “select at least” and “1” on a Checkbox Group with 10 checkboxes then the Recipient assigned that checkbox field can select “1” or up to “10” checkboxes in the selection. So the validation is acting as designed. If you want only “1” out of “10” checkboxes then you should the validation as “exactly” and “1” or use the radio button field instead.
In order to better answer or to cover your exact scenario, I would ask for the exact number of checkboxes on the document and what is the expected outcome when a Recipient goes to fill out that field?