I thought the manga had talked about "Lady Idea" previously, but maybe it was just another mistake.
I checked Manga raws, and everywhere its always Idea-sama, which technically could be translated as Lady Idea as well, assuming that you know the characters gender already.
Japanese language is highly contextual.
Many of the terms are bi-gender, aka., can by used for both male and female (which is why Machine translation always make error with gender identification with Japanese).
So, its important to keep in mind to always cross-reference the scene and the contents in the scene while translating.
If the gender is unknown, then its better to use a more gender-neutral term instead.
Male/Female terms which can also work for opposite gender would also work.
Like for example "Lord".
While, its generally a male term, it has been historically also used for female rulers as well.
Though that's not the case with Lady, which is always female specific.