we have a street rescue that has similar behavior. frankly I think she was "mistreated" as a youngster - likely by young children - who didn't understand and were not taught that picking up the cat by its tail is not a good idea, for example.
which may explain her being dumped on the street - situations involving moms, kids and cats-that-draw blood usually don't end well for the cat.
she's fine until I disturb some 'trigger' - the fight or flight thing kicks in and she's a fully armed _big_ kitty and knows how use 'em.