How to post a comment on Facebook Page as User, not as Page

I want to post a comment on Facebook Page as User. The user is admin of the facebook page. I tried that my app requests the following URL with the user's access token.

https://graph.facebook.com/[POST_ID]/comments

But the comment was posted as Page account.

I was able to post on Facebook Page as User. My app requests the following URL with the user's access token.

https://graph.facebook.com/[PAGE_ID]/feed

It's successful. With the pages's token, the post was successfully posted as Page account.

But comment and like can't be posted as User. Is it a bug of graph API? Please help me.

If you post with the User's Access Token it will show up as being from the user. It will only show up as being posted by the page if you use the Page's Access Token obtained from me/accounts/ in the GraphAPI.