Yea. It occurs to me .The new post which was created within centain time will be allowed to delete .That is to say , the data has not written into the block ,for which the post number does not change .You can try a experiment that create a new post then leave it more than several hours ,then you can not delete it and the post number shown in you profile will add 1. So that is not the bug . How it works is excatly the design concept of the developers .you can check more source code to prove it .
RE: posts-counter is not counting correctly