The term "occurrence" in the policy generally signifies an unexpected event; under state law, except for some strict liability events, the test is actual subjective expectation, not that which a reasonable person would expect.
The challenging of claims by the insurer did not violate state trade practice laws.
http://www.ca2.uscourts.gov/decisions/isysquery/85b366f3-f243-43e5-81c8-b4640a784328/1/doc/16-2999_opn.pdf#xml=http://www.ca2.uscourts.gov/decisions/isysquery/85b366f3-f243-43e5-81c8-b4640a784328/1/hilite/
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.