It looks like Kolby got registered for two separate camp registrations, from this year and last year:
1.) Pre-Teen Camp Registration (2022): https://rock.cfbc.org/web/event-registrations/1202/registration/25889
2.) Kids Camp Registration (2023): https://rock.cfbc.org/web/event-registrations/1398/registration/38448
You can see that the target groups in these registrations are the groups that Kolby was added to:

The date that Kolby was added to the wrong kids camp group is 4/26/23 at 8:39PM, and we can see that while there was a payment for Sawyer's registration at 04/26/23 at 8:34PM, Kolby's payment was made the next day on the 4/27/23:


We can see that Taylor used the impersonation link from a registration related email/link to pay for Sawyer's registration, and that he then went somewhere that required a login where the returnurl is secured (even though that impersonation token is loosely secured and let me see the rest of his account as well.)

From this information, I am surmising that Taylor Delleney either accessed an old kid's camp registration for Kolby when trying to either register or pay for both his and Sawyer's registrations and it accidentally added him to the extraneous group approximately 5 minutes after the Sawyer's payment was made. The next day, he used the correct links to make a payment for Kolby's registration.