Hi muahchee,
I apologize for all the trouble it has caused and sorry about your time.
As per your description, may I know double confirm with us are you trying to create a Microsoft form duplicate link? If yes, you can to copy a survey/quiz form via Go to forms.office.com and sign in with your Microsoft 365 work or school account and on the form you want to copy, select three dots “... “ More options in the upper right corner of the form tile then Select Copyto see the result. ****
Open the problematic form> Share> Anyone with the link can duplicate> Copy> Paste the copied link in new tab> Duplicate it> Share to check the outcome.
Meanwhile, could you please confirm does issue happen to only specific form and also please confirm how did you create a form it will help for us to narrow down your issue.
At last, can we know whether you are using the Microsoft Forms with Personal Account or Work/school account?
I appreciate your patience and understanding.
Best Regards
Waqas Muhammad