I am glad that the update resolved your issues; however, I too have updated my software to 6.1, but calendar still is not saving the shared calendar permissions. It is the same whether I am on my iPhone, iPad, or on my Mac Air. I guess this bug has not plagued enough people for apple to address. I do appreciate your response though.
I too am having identical issues. I assume it doesn't have anything to do with making the calendar public, right?
We should be able to share private calendars with others, and preserve our "read only" sharing preference. Can't figure it out.
As soon I close and reopen the calendar sharing preferences, it has switched back to "view & edit" every time.
I'll keep looking for answers to this one!
I figured it out.
Something about the icloud sharing permissions is getting snagged. The easy fix is unsharing the calendar with each person and reinviting them.
The big thing is to set the sharing permissions BEFORE they accept the invition. Once I did this, all my permissions stayed constant.