I'm pretty sure that the way she was portrayed in the Hyuuga Sisters is FILLER 9000%.
The same goes for 99% of all the "stalking" we've seen of her - either FILLER or FULLY NON-CANON (eg. Naruto SD).
In the MANGA, she's been shown WATCHING him like once or twice - and it mostly looked ACCIDENTAL at that.
Anyways, she never meant to HURT or DISCOMFORT him, which is already taking her OUT of this category.
The verdict:
Definitely NOT a stalker.