Email from Uni claiming to be my "firm"

The other day i got an email from Queens Belfast saying they are delighted that I have chosen Queens as my firm choice. I have not even chosen my firm yet as Queens is the only uni to not get back to me on UCAS so i am very confused. Queens would not be my firm choice anyway even if they do give me and offer so im a bit worried. Is this just an automatic email they send to anyone that applied or did i miss a step in my UCAS? Was i meant to have chosen a firm already? Also to note is that after i got 3 offers from others unis I then added queens to my application, if that makes a difference.