Access/edit problem with older meeting agendas

I am helping Covenant Toastmasters, club #4479, with a quirky problem accessing and editing older agendas.  If I access an agenda from 2015 or earlier, the agenda can not be edited and the meeting agenda page gets stuck, not allowing either the blue arrow buttons or the drop down box to get to another agenda.  Clicking on "Click here to reload from server" doesn't fix it.  One has to log out as Admin then go back in to get out of the quicksand.

Why are you editing agendas that old?
How are you logged in, as member, VPED, or site admin?
What browser are you using?

Brian,
1) Members did not sign up the right way for prepared speaker slots "in the old days," and the current admin, who came in as the club's area director, offered to go back and clean things up.  She told me that members never properly selected projects when signing up for speaker slots.  Going back that far, of course, means legacy manuals, not Pathways.
2) Both the VPE and I were logged in as site admin, me via the ambassador tool and she directly.
3) I was using Firefox; I don't know what she was using.

If the answer is "the system prohibits editing of agendas more than N meetings old," so be it.  It's just that FTH seemed to "hang" when we went back to 2014/2015, not responding to the top-of-agenda buttons.
Art

Only one person can be logged in as the site admin at any time.