The HSK6 textbook has this example of the inappropriate use of a subject.
It argues that it's incorrect because the sentence begins with the subject 他, and switches to another subject (i.e., 字画) without declaring it.
I'm interested in applying this grammatical logic to the following sentence from the same textbook (it's intended to be a grammatically correct sentence):
In particular, the subject in the first part of the sentence is 她的脾气 ("her temperament"). If I were to apply the above logic to the second part of the sentence, the subject of the second part remains 她的脾气, so it should be translated as:
Her temperament is not good, [and] [her temperament] often doesn't know why [it] suddenly gets angry.
There might be some reason why the above grammar rule doesn't apply here, but I don't see why. To me, it looks like it violates its own grammar rule, but it'd be nice to check this.
Question: Does the sentence 她的脾气不好，经常不知道为什么突然就生气了 violate the textbook's own grammar rule regarding inconsistent subjects?