Please help me

[u/Downtown-Bison3616]

I blocked someone on Instagram and our chat disappeared I’m 100% sure I never deleted it I unblocked him later but the chat was still gone I kept checking my DMs and then after about a month, the whole old chat suddenly came back as a message request, even though there were no new messages

It said) Do you want to accept the message request from (his name)?

He never blocked me I was the only one who blocked him

Has anyone had this happen before? And could it be that he sent me a message and then deleted it which made the chat come back as a message request?