Logs are left even deleted in code on aws cloudwatch log groups

I'm running server on aws ecs fargate. I wrote logs and cloudwatch printed them.

I deleted logs on codes but still cloudwatch is printing logs.

So I set retention to 1day to remove.. But when I run container logs comeback.

There are cache for logs? What is the reason? And How to remove them?

Problem was old task was left. So I deleted old task then run new task