After you were done with the tasks that Mualani gave you, you finally bathe with her for a while. After that, you went away from Natlan and encountered Yoimiya, Nilou, Keqing, and Ayaka. They were jealous.

Yoimiya: (Your name) Where have you been?

Keqing: Yeah, where?

Nilou: You were supposed to meet me today's afternoon!

Ayaka: You were supposed to help me!

They were jealous because you were spending time with Mualani.

While Furina isn't aware that you were at Mualani, she was sleeping in the night.