From the article it appears the eviction notice was because of the dog’s behavior. The act does state, “A disabled person who does not properly manage his/her unruly, destructive, aggressive, or disturbance causing animal can be evicted.” Keep in mind though those terms are very likely defined in local ordinance as well as California statute. Was such a label ever officially determined to apply to the dog? If so there are avenues of appeal.
It is possible the dog is unruly, destructive, aggressive or causing a disturbance.
Dogs can get that way living in an apartment.