When you do a cut and paste, there are three options if you right click to paste Keep Source Formatting, Merge Formatting, and Keep Text Formatting. Hover over each of the choices and a preview drop window lets you see what you will get.
If you merely Control V to copy you get the Keep Source Formatting (default), however immediately following the paste is a small window showing a clipboard if you hit the down arrow the three options available with the appear. That window disappears when you type either a modification in the copied text or anything after it.
Hope this helps, I wasn't able to recreate the problem so I can't be positive that this would solve your particular problem.
Thus says the LORD, "Let not a wise man boast of his wisdom, and let not the mighty man boast of his might, let not a rich man boast of his riches; but let him who boasts boast of this, that he understands and knows Me, (Jeremiah 9:23-24a)
"Defenders of the faith are inclined to be bitter until they learn to walk in the light of the Lord. When you have learned to walk in the light of the Lord, bitterness and contention are impossible." --Oswald Chambers, in Biblical Psychology from The Quotable Oswald Chambers.