The adverb of 'untypical': in a way that is not usual for that person or thing. It has two jobs. Most often it stands in front of an adjective and means 'unusually, for them' — 'She was untypically quiet at dinner', 'The traffic was untypically light this morning'. Read that as: quiet is not how she normally is. It can also attach to a verb: 'He untypically arrived late.' The whole force of the word comes from the comparison hiding inside it — it only makes sense if the reader knows, or can guess, what the usual state is. That is why it so often appears with a person we have already been told about. It is a formal, written word, and just like 'untypical', its more common partner 'atypically' rules in scientific writing. In speech, people simply say 'unusually' or 'that's not like her'.