You are correct, this is a bug. I've fixed it and that fix should be showing up in a maintenance release soon. Keep an eye on the release notes. If this is a major inconvenience for you let Support know and they should be able to get you a preview build.
Thank you, Logan. I appreciate the update. I can wait for an update; I've made it this long without built in choropleths. I'm just glad I wasn't missing the painfully obvious.