Miscommunication in friendship/relationship?

Hi! I’m 22F from UK and I’ve been in Japan for around 8 months and I met this Japanese guy (25) on a night out around a month and half ago. We became friends and we texted pretty often. We always say morning/good evening etc. etc. in the UK we often reply back quickly when we are interested. My friend however, replies back pretty slowly and often after saying hello, he will say what he’s doing and say he has to be off. But! He always texts first!!

Example: (in English)
Him: good evening, are you still awake?
Me: yes! Good morning, What are you up to today?
Him: I’m going to see friends soon.
Me: oh cool! What are you going to do?
Him: breakfast at cafe!
Him: got to go bye. Sleep well

This was like a two minutes conversation but this kind of situation happens a lot. I can’t tell if it’s culture difference or he’s just bored lol?

Thank you ☺️

by Jun3_Buggg