Power Apps: Checkbox is checked when in "Edit" mode, but not when users use it

Displayed on a screen is a single Checkbox beside a group of images. The data for this gallery is obtained from the default value of a checkbox, which is stored in another SQL database. This checkbox is selected when I enter edit mode, click Play, and then choose an item that should have it checked. However, when I replicate a typical user's actions, the requisite checkboxes remain unchecked.