Why? Are the posts always supposed be in order of time? …because that’s not what I’m seeing.
I reproduced by selecting 10 posts from the bottom of a long topic and moving them into a new topic. Then I selected 3 from the top of the same topic and moved them into the same new topic. The 3 are showing up at the end, the 10 are showing up above the 3.
If that’s not what you were implying, ignore this post 