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The elderly person had to be a resident of the state where the will and trust was executed in order to be valid, that is the first thing. Secondly, if the real estate was in NJ, then NJ law must govern all real estate that is located in NJ.
Since your mom did not die in Arizona, the will has to be probated in NJ, which is where she was a resident at the time of her death.
I do not know why the attorney who executed the new will and trust did so, unless he was not told she was not domiciled Arizona at the time he made it. Domiciled is different from staying in a state for a short time as domicile is the place where you call home and always intended to return (primary place you reside).
The second will is likely going to be open to challenge and will likely be invalidated and the previous will and trust reinstated based on the fact she was not domiciled in Arizona when it was executed (even if domicile is found in Arizona, the NJ property still has to be governed by NJ law).
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