I'm assuming that Analia couldn't see Haru's eyes clearly both due to choosing not to look too closely and, more importantly, because of how dark it was whenever she looked at Haru. Hard to ignore someone's face when the sun is shining directly on it, I suppose, and as Analia mentioned Haru had a strong sense of determination in her eyes that reminded her of the late emperor. Still seems kinda odd how she just switched like that, but maybe that's the power of Haru's blood combined with Haru showing proof that her mother did indeed love the emperor in the form of the ring. I'm glad that Haru in universe at least addressed the sudden change and how uncomfortable it was, cause if she just ignored it and glossed over it I would have to start doubting Haru's intelligence.
Edit: Ah, right. Forgot Haru was also blindfolded most of the times Analia actually spoke to her directly, so no wonder she couldn't see Haru's eyes. Went to check the previous chapter for a separate reason and only then remembered the blindfold.