I was told by someone who has an account for another instance of Misskey and an account for an instance of Pleroma about this.
I asked him to do the same thing, but he said he could not reproduce it.
It seems that the problem is only reproduced with my Pleroma account.

After almost 2 months of struggling with this issue, I decided to give up and get a new Pleroma account.
I decided to give up on this issue and re-acquired a new Pleroma account and started using that one.

Sorry for the trouble.