God judges us on the first day of the year and it is only sealed on the 10th day of the year what will happen that upcoming year. so how can people die in between those two days?
I asked a similar question years ago at Aish HaTorah's "ask the rabbi" service. My question was:
Our tradition says that on Rosh Hashana God records us in one of three books -- immediately for life, immediately for death, and "defer until Yom Kippur". Doesn't this tradition have unfortunate implications for those who die between Rosh Hashana and Yom Kippur? Aren't we to presume that no one is entirely evil (thus we don't say kaddish for a full year, etc)? How do we resolve this conflict?
The answer I received (I do not know if I have permission to quote it verbatim) said that the source for the evil being sealed for death on Rosh Hashana is Bavli Rosh Hashana 16b and specifically the Tosafot there. But, the Aish rabbi went on to say, the death and life talked about there refer to Olam HaBa, not this world. Therefore, a person's death in this world says nothing about how he was judged with respect to Olam Haba. People die in early Tishrei, but that doesn't mean they were judged for death on Rosh Hashana.
(I originally asked this question after a family member died on the second day of Rosh Hashana, though I did not share that motivation with the Aish rabbi.)