The text replace removes the carriage return after a line it modifies and appends the line below it to the line that was replaced. This behavior does not happen with the FB4 Text Replace that was deprecated.
Please see the attached files with screen shots of this behavior.
After reviewing my setup I did find a carriage return after the replace string. With this text/replace action it is easy to miss this, since you can type more than one line in the text box for the find string and replace.