I noticed with myself and another leader that are leaders in both our Troop and the Pack that the calendar behavior may need an adjustment. In my current state I have calendar edit access for the Pack but not for the Troop. However, when in my Troop profile it looks like I have calendar access (I assume because it picks up on my Pack permissions). Yet it will just take me to the 403 error page with the message You don’t have access to this trail (which is correct since I am under my Troop profile and I lack Troop calendar access).
It seems logical that the create and edit event options for the calendar would not display based on your current selected profile’s access. In my use case I shouldn’t see edit events or the + sign to add an event when accessing the calendar from my Troop profile (even though I can see Pack and Troop calendar side by side).
At a minimum it may be better to redirect to a help page about needing the Calendar Edit access permission than a generic 403 error page.