I'm an international pre-final year undergraduate student. My undergraduate degree consists of 8 semesters and I'm currently in the 6th semester. I'm hoping to apply to US mathematics graduate schools this Nov-Dec, for Fall 2021. I missed a final exam in the 4th semester due to medical reasons and was supposed to re-appear for it in May 2020. However, now that re-test will probably be scheduled in December due to COVID and I won't get the results before the US application deadlines this year. Moreover, I was not issued any grade card for that 4th semester.
Now several US math graduate programs say that they only require unofficial transcripts in the online application and that hard copy official transcripts can be submitted later. So would it make sense to apply anyway with only my 1st, 2nd, 3rd, 5th, and 6th semester grade cards, and with the 4th semester grade card missing? Would I have to explain that one missing grade card in the online application? If yes, how? Say, would a letter from my head of department, explaining the situation be helpful? I will hopefully get my 4th semester results by March 2021 though, so I think I will later be able to send the official hard copy transcripts in time, in case I get an admit.