I think Chloe just calmed down.

The other disconnect here is when Max jumped to the back her and Chloe had just a row to the extent that when Max left the vehicle all she got from Chloe was eye daggers. But the next day their sleuthing together like it never happened- check Max's phone when she gets back. Chloe texted her to apologise, because she calmed down. When she was that upset about Rachel and said all that stuff about it being her dad and Max's fault she was just angry. And like many angry people she said a bunch of stuff she doesn't really mean. When the anger passes the realisation she's been harsh to people who didn't deserve it kicked in, so she texted that apology to Max. She also realised that Rachel is still her friend, she still loves Rachel and she still wants to find her. Now she's calmed down a bit.