If I merge a post that has attachments to another post that has reached the character limit, it gives me a character limit(1000) error and halts from merging the post, but the attachments still gets copied/carried over to the post I pointed the original post to merge to.
If you go to the post that the attachments got copied/carried to and delete the attachments from there, the attachments from the original post also get's deleted.
Also while attaching images and clicking to insert all as thumbnails, I often get the first attachment inserted only. Meanwhile if I remove the first inserted thumbnail from the rich text editor and click on insert all as thumbs again, it works as it should.
Hope that makes since