As I show you in my book, you need to Duplicate, not Copy your title if you want to reuse it. To Duplicate a title, right-click it in your Project Assets panel and select the Duplicate option.
When you Copy a title, you make a clone of it -- and when you change one, you change both.
thanks! but what about if i have a combination of titles on work area and I want to duplicate them (and change the text a bit)? it's difficult via project assets if i have to do it one by one(?).
Sorry, but there is no other way to do it.
If you copy and paste, you're just going to make clones. You need to duplicate not copy the title(s).