It is certainly debatable what an ideal pass rate for licensing exams should be. If the pass rate is high, that means almost everyone gets through. Then the tests don’t serve a meaningful function. (That’s pretty much the status quo.) If the pass rate is low, it raises questions about the validity of the exam, given how much time most examinees spend preparing for it. But what makes a pass rate too high or too low? Given that the exams don’t do much of anything anyway, it’s hard to say for sure.
But it does raise eyebrows when pass rates for a single exam fall off a cliff, as seems to have happened for California MFTs over the past year.