apparently this is only when using the API Console, which is (or I guess was) my main way of testing the various endpoints
about 5 years ago
Yes there are some known issues with the API Console as it relates to empty arrays and null data. Those issues have been reported and will be addressed in the near future. There is a bigger issue that we are planning to address which is better utilities for testing.
In the meantime, I suggest using a Postman chrome extension or one of the many commandline REST clients like curl to test your endpoints.