Why is he behaving like this?

So there’s a guy who I have been talking with recently.. I always reply to him as fast as I can but I’m busy nowadays so I don’t know why he replies late just coz i reply late to him sometimes , I wasn’t ignoring him I was busy for real and he always does this so it’s a red flag for me and today I was talking with him on WhatsApp he was online he thought that I’m gonna think that his network wasn’t working properly but I know that he turned WhatsApp off from using his wifi so what’s should I do?
Why is he behaving like this?
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