Checkboxes firing on all records instead of the selected record

I'm building a form that contains a subform to list records as a datasheet. The fields on the subform are sourced from a saved query. To the subform, I added a checkbox control to serve as a record selector.

Here is the problem: When I click on the checkbox of specific record on the subform, ALL the checkboxes on all the records display a check rather than just the one I clicked. I cannot figure out what is causing this undesirable behavior.

Any insights or suggestions to fix this is much appreciated.