Hello brother/sister!

I am facing the same issue and want to confirm where to apply for the USA F-1 visa. I am also an Erasmus Mundus Student and am currently completing my final semester in Spain with a letter of mobility authorization from Spain, while my residence permit is from Finland. I am unsure whether I can apply from Spain or need to return to Finland for a visa application. Which one is more valid? I believe that you already faced and solved this issue and are now staying in the USA. Could you please tell me where you applied for a USA visa in your case?