Duplicate form, receive emails twice. What now?

I have encountered this a few times now: when I duplicate a page with a form on it and I adjust the new one slightly (new edition of the same journal, so apart from the name everything stays the same as on the original) then something strange happens:

When someone uses the NEW form I receive an email concerning the NEW edition of my journal, so that is correct. But I also get an email that looks as if that person filled in the form about the previous edition, the ORIGINAL form I copied. The other way around too. Quite confusing, because in reality they only filled in one form.

So the duplicate form triggers the original one and vice versa. The only way to prevent confusion seems to be changing the names of the input fields but I still get two emails. How can I escape this? I must be doing something wrong.

That shouldn’t happen, there must be an issue with page duplication, we’ll take a look.