I'm currently at war with the Ottomans, but I got this message:

and when I checked, the Canal decision is back in my options (but I can't play it again):

I've attached the relevant turn files:
[ATTACH]21579[/ATTACH]
at worst I can write a script for it to appear in 1882 but I wonder if this is due to the Egyptian CP going over 101 in Suez? That is the only odd thing I can see about the province that might have triggered both the loss of the decision and the inability to replace it
as ever, thanks ...