Event related with Leads shown to Guest User even without Access

[Reshav-git]

I have configured this app, and for guest users, it is showing events that are related to leads, even though I have not provided any access to leads to guest users. I have also created a custom object to show events to guest users as it was mentioned in the document, and it was not having the same behavior in the developer sandbox. In the full copy sandbox, an event related to leads was displayed, which is not supposed to be displayed to a guest user.
Any comment or suggestion will be highly appreciated.