I think that's expected behaviour because in when we enter a value in a rich text editor for a property then the value in the clipboard will be stored with HTML tags. When try to show that property in the text area, it will show the tags.
I would agree with the prior comments. This sounds expected because the RTE is designed to maintain and store the rich content which requires HTML or other associated markup to dictate the rich nature of the text. If it did not, then it would simply be a text area.