Autoform custom validation not showing error messages

Asked this over at stackoverflow: http://stackoverflow.com/questions/32302359/meteor-autoform-custom-validation-not-reactive

Basically, my custom validation check runs, this much I know, but the error message isn’t rendered on the field. Console log shows that the error isn’t registered with SimpleSchema. I’ve double/triple-checked the context name and that my schema is being used. Not sure what to try next.
Help is appreciated, thanks!