Thank you aswell for finding the mods useful.
This does like a strange occurance, i haven't seen anyone else mention this so far.
It may be related to the folder location of the game, not allowing saves but in case it's located similarly to the first game then that's not it.
In some weird cases it could also be Operating system related but i can't say i have much experience there.
By "isn’t selectable" do you mean the save is there but is greyed out or something?
Does the save file exist in your "save" folder inside the game folder?
Either way i will take a quick look tomorrow over the mod and see if there's anything strange going on there.