Is it possible that you hit the Program button mistakenly and then accidentally miscalibrated the module? I'd try running the calibration: http://erica-media.s3-website.eu-central-1.amazonaws.com/Black_MIDI-CV_Manual_200x166_E_Preview.pdf

(NB: MG's forum doesn't like the underscores in the above URL...try going to the page for the module itself: http://www.ericasynths.lv/shop/eurorack-modules/by-series/black-series/black-midi-cv-v2/)