Swiss is notorious for taking long to issue e-tickets, in particular when you do rebooking that sometimes can take over a week or so until the e-ticket is (re-) issued...

I would not be worried about price changes - I would be more worried about the fact that system autocancels reservations without valid ticket after a certain time. (Swiss does that with the travel agencies, but I am not sure if they also apply this rule to themselves...)

Als the 24 hours: IMHO does only start counting from the point in time the have issued the ticket.

What I do not understand at this age and time is why at this age and time after you had a phone agent typing all your Details into the system and quoting you a Price (aka "Reservation") you still Need a second agent on the othe side of the planet to push some buttons to really make "it" happen (aka "issue a ticket").

For those interested into history: This logic still comes from the days when people wrote Airline tickets by hand and had to phone the Airline to make a Reservation. At that point they had to link the Reservation with the ticket by quoting the ticket number within a certain time Limit....

The hilarious bit was when they changed the flights on the ticket: the literlly put a Little sticker on the flight number on the ticket, overwrote it by hand and put a stamp on it to prove it was done the airline... that is why some elderly airline employees still speak about "stickering" when they mean change flight numbers on a Reservation...

Yes those were the days, but they are gone (expect for Swiss who still abides by this logic....)