I've found a bug, but I don't have a good reproduction cuz it's all wrapped up in my company's private code. I'll try to describe it and maybe we can refine it through discussion before I write up a github issue
In clojure.test, the function test-vars calls each-fixture-fn, wrapping calling test-var on each test function being run. test-var wraps the test function in a try-catch, and if there's an error in the test, it logs an error directly.
This is to say that the once and each fixtures don't see any exceptions thrown by the test because the fixture wraps a new anonymous function that calls test-var on the test function
kaocha wraps the test functions directly in kaocha.type.var with the reduce call. Then the wrapped test is executed within the try-catch block, so the fixtures see the exception.
if the fixture catches and doesn't rethrow the exception, then no error is reported and the test is treated as successful
I hope I did this right: https://github.com/lambdaisland/kaocha/issues/367
Interesting! Thanks for reporting!