Do you see that weird grey-and-black rectangle on the end of the line?
I think that's the bad hidden character. It might not be visible in a text editor. It probably got there through some kind of copy-and-paste operation.
I think if you delete everything past the # on that line, the problem should go away.
Check again with the grep afterwards that it's gone.
Oh, gosh. You’re right one more time… I had noticed that stuff before… I was suspecting from the beginning. And yes, I used this copy-paste method there. Now I remember… Ok, I’ll take it out and see how it goes… Wait…
That means that when I set the subdomain it will show on that list, right?
I think I know what the problem was: have you came across that situation where you press tab and then a long red space shows there? So… that’s what happened. However, I didn’t know what it meant. Now I know what that heck may cause. Why?
And Certbot would generate a certificate that covers all 3 domains.
From that description, I'm not really sure. Things can get a bit weird when you're copying text from Windows into a Linux terminal, unless you're sure that you're dealing with "plain text" on both sides.
That’s normal for a Ctrl-C, assuming the last line of that error is KeyboardInterrupt. Maybe Certbot shouldn’t print a big scary error like that, I’ll file an issue for it. (Edit: filed)