CFA Level 2, more mocks or CFI topic tests?

I am under the impression that since the CFI is giving so many by topic tests online, that the topics they will create questions from are probably in those tests. I read that a lot of people who used 3rd party mock tests ended up doing poorly because the provider did not test on the specific things the CFI put on the exam. Because there is so much material to test from I don’t see how the CFI would test something they didn’t go over on their own by topic tests.