How overworked would a doctor need to be to hallucinate you told them about microdosing psillocybin when you never said anything of the sort? (And how easy is it to then convince the system you're not a recreational drug user when it's in your medical records you admitted to drug use? Does this change if you're from a background more likely to be stereotyped as drug users?)

The humans are probably making mistakes like writing 100mg of something when they meant 10mg, which can also have dangerous consequences, but to an extent it's known this happens and there are processes to catch it. The type of mistakes and how much trouble and distress they cause matters as much as the number.