Jedi are very good at picking out Sith Lords
....uh...they aren't. Plageus, Sidious, Tyrannus, Traya all hid either amongst the Jedi or so close to them that that they could basically breathe the same air.
However, let's talk about the little miss for a second here.
Ciaran's fighting styles and force abilities are as follows:
> Form 2 Makashi - Trained by Dooku
> Form 3 Soresu - Trained by Obi Wan himself
> Blazing Chains - Separate Force Tradition, used by a specific bunch of Force-sensitive Pirates primarily
> Matukai Self-Reinforcement - Separate Force Tradition, adepts are nomads
> Luka Sene - Separate Force Tradition, adepts are primarily Miraluka
> Shatterpoint - Universal ability, incredibly rare, unknown by pretty much everyone not named Asajj
> Buried Presence - Modified to be perpetual, universal ability
None of that exactly screams Sith Lord, even Makashi, that was taught by Dooku, could not be considered as proof of any kind of association with the Dark Side as the Jedi themselves use Form 2. Lightsaber styles and indeed the weapon itself technically isn't something that is unique to the Jedi and Sith anyways since with enough skill even a non-Force Sensitive could use them. Even then, Mace Windu has absolutely no room to talk about Dark Side fighting styles, what with his part in the development and his mastery of Form 7, that has been the reason behind the fall of at least three Jedi iirc.
Ciaran has portrayed herself as an exceedingly eccentric business woman with an incredibly deep mystery as part of her background, that she's a Miraluka already gives her leeway regarding her Force Sensitivity, then the nearly successful attempt on her life with Dooku saving her life and her recuperation afterwards gives her a motive behind learning all kinds of ways to defend herself. That she's an eccentric and Force Sensitive means that some of those methods would definitely involve the Force. Not to mention that Force Sensitives could spontaneously develop certain Force Abilities, such as precognition, so Buried Presence could be explained away as Ciaran's subconscious desire to fade away into safety.
Darra's report about her dealing with the Hutts only adds to the mystery, but honestly, no business person worth their salt would not deal with the Hutts at some point or another. Even some Jedi deal with the Hutts and other criminal elements.
Long story short? Ciaran isn't throwing up any of the traditional identifiers of Sith Lord-hood, furthermore, she herself isn't a traditional Sith Lord either, remember that she is Darth Traya, the betrayer of the Jedi and the Sith, so why should she be immediately be identified as such, especially Ciaran has made it her mission to hide where she came from and what she had to do to become what she is now. It makes no sense, whatsoever within the narrative that the Jedi would learn about her.
Anakin is the only one, again aside from Asajj, who knows who Ciaran
really is (though I can't remember if he knows that she inherited the title Darth Traya) and she set him free (weird how Revan's Sith teachings could end up saving the Jedi Order, again) to think about what being a Jedi means to him, he isn't going to talk, especially since she is his Final Solution to the threat of Darth Vader.
