This hint is to differentiate between these two very similar cards nid:1534256975117
"What is the most common cause of secondary hypertension in young women?
{{c1::Oral contraceptives}}"
Many people get tripped up. The hint is not saying that OCPs do not cause hypertension, the hint is saying the answer to this card is not OCPs, its something else.
If you want to remove this hint, You can remove this yourself by right-clicking on the card → go to AnkiHub protect fields → select the field you want to protect → remove it and it won’t be overwritten