If dying at a little over 1 yr old was normal, there would be no more boas. So , it is not normal.

Many mistakes can be made in the husbandry of boas, with the number 1 reason at too cold of temps for too long and too much ventilation, or better put, too little humidity for too long.

That said, there are some individuals that do not survive, like the other poster said - born weak or with a genetic flaw - no matter how well they are kept.

But again, the #1 reason is improper temps and humidity for too long a period. Burms seem more forgiving with mistakes compared to boas. But boas rule