I felt like the early chapters kind of portrayed her as kind of flaky but she has been a cartoonishly good partner so far.
I think there's a few ways to read that/reasons that might be the case:
-Kanata has known Hana for a long time (and has been stringing her along for attention after noticing her feelings for a decent chunk of that), so she's probably more equipped for/comfortable with this relationship than with some guy she wants attention from
-Kanata is kind of warped because she's had a lot of attention from boys and a lot of scorn from girls because of that. She likes the attention, but from what we've seen this is the first relationship she's put a ton of effort into (iirc it's the first time she did the confessing). Would sort of make sense why this one is going better than previous ones
-You could also read it as that her previous relationships were comphet but that's really not clear (although it would explain why they didn't work)