Heidi is frustratingly consistent at hallucinating stuff. I've seen it in almost all of the dozen or so summaries I've had from medical people recently (surgeon, physio, consultant). A GP I know tried for a month and then was like 'it's not worth the risk exposure to me or my patients'.
I know at least one GP that has stopped using Heidi Health for transcription. He (and as I've noticed with transcriptions from my medical professionals) has noticed many errors, far too many to be comfortable. Things might improve, but not yet.