Any parrot can shift preferences, and sometimes without apparent cause. But Salty likes my oldest son the most I think. Amybe equal to me? But my son is not a big fan of animals that bite or nip, so he stayed pretty aloof from Salty. Only time he would let him near is washing dishes where Salty would sit on his shoulder and sing with him. Now my youngest son, he helped wean Salty and they got along great, but when he moved out, Salty did a 180 and now Salty goes into full attack mode when he visits. My wife also helped wean him, but she has always been hesitant about 1 on 1 with Salty, so he more or less tolerates her. SHe can get him out and into his cage and retrieve him from the floor with no issues, but in example if she tries to give him a treat during training sessions, he will lunge and if he connects, he delivers. Oddly during this mating season palaver, he seems to be a bit more open to her interactions - last nite he hung out with her on the couch and played a bit - a first time.
I would not over worry about shifting preferences. While spontaneous very occasionally, it most often occurs during or right after puberty. And even then I think some folks just dont know how to deal with the jeckyl/hyde aspect of puberty personality shifts, which DO happen all the time, and just back off unconsciously or dont know how to reintegrate themselves.