CT Why didn't Vader sense Leia (in-universe explanation)?

There's no official one. Although I agree with the original responder that Luke had some minimal force training, I also think Vader just wasn't looking for the force in Leia. It was Luke's impressive piloting that caught Vader's attention, where Leia was more of just a annoyance to DV.

 

I think it is because leia didn't have the formal training that awakened the force in her on the same level as Luke did due to his training with Obi wan...however these are suppose to be the children of Anakin, the most powerful Jedi ever, and should have exemplified force powers when they were children, similar to Anakin in PM and the children in the CW Holocrom Heist arc..leia was powerful enough to remember her mother as an infant and to know intuitively that Luke was her brother, however this does not cover the possibility of force powers as a child...she even tells Luke " you have powers I could never have..." In ROTJ inferring that she never had force powers manifest as a child...

In the end I think Lucas and the creators of the CW really back peddled into the story because they are telling the story backwards and that it doesn't make any sense that Vader wouldn't sense Leia...I always hated the Holocron Heist arc, showing toddlers moving stuff with their minds, because it just doesn't make sense that toddlers would do this still in the OT era( there's no reason to think that it stopped after the pt
Era).I think it would have been better to just "sense" that a child was powerful or exemplify it in I a way like Anakin did..through a skill, not some telekinetic means, which should be something that needs to be harnessed through training...to say that Jedi are extinct In the OT era but with the notion to still have toddlers out there moving things with there minds is pure nonsense...as much as I love the OT and the CW show they really messed up on this one...I think they got a little too ambitious

 

Leia was raised to fight with her mind, not the Force. She likely never even knew she had the potential. She can't exactly hon a skill she doesn't think she has.

Vader didn't sense her for two reasons:

- Because Leia never knew she had the Force, she never tapped into it so her 'signature' for lack of better word never spiked.

- Vader thinks he only had one child, and that child died with Padme. When Luke arrives on the scene using the Force and swinging his lightsaber, Vader homes in on him. He never considered Leia would be his daughter. Of course he found her dangerous, she was one of the main leaders of the Rebellion. He just didn't think she had any Force potential at all, much less that she was his other kid. Another way to put it is this: why would he think he had another child, a Force-sensitive child, if he had believed for 20+ years that his one and only child had died?