What conflict initially arises between Captain Smollett and Squire Trelawney?

I believe the correct answer is that Smollett neither likes nor trusts most of the crew, which offends Trelawney, who hired the crew.

Captain Smollett is first offended because he wasn't aware of the fact they would go treasure hunting, and then he expressed his dissatisfaction with the crew, to which Trelawney asked whether he hates him as well, showing that he too is offended.