I did think it was weird that the pool date ended so quickly, but I didn't actually put 2 and 2 together and realize it was out of order. In any case, Chapter 22 was pretty great. One of my favorite parts about this series is, despite how Chiaki is ostensibly a tomboy, Harumi still really loves how cute and girly she can be. Normally you'd expect them to go "Oh, she's so cool and handsome (like a guy)!" But with Harumi, she's just flat out gay for Chiaki.