mdd, please consider first that the Ramban (I think he mentions this in his explanation of hanistarim in parshas Netzavim). distinguished between a “transgression” of which the perpetrator was totally unaware, and a shogeg, which was done intentionally without knowing the seriousness or even if it was assur.
Also, for a different take, see this post by Chaim B. from the Divrei Chaim Blog, from last November.
“lav she’ain bo ma’aseh b’shogeg
Not pashut that she was a shogeg.