@uriel : yes i can, i see in the code and this only a flag to false in the method add_trait().
But I think that is not a bug. You really want that i put them as permanent ?
Further in that thread they say that girls can gain temporary versions first, then, after some time, if still being tortured, gain permanents. But this function were broken somehow during the torture code overhaul, or never worked in the first place.
Anyway, i think girl can't stop being a masochist once she became one, or regain her will while being constantly used as a slave. Not mentioning getting back her mind without help.
Also those traits are fun and very hard to gain, why make em temporary?