We're moving from Marketing Cloud Classic to Content Builder. All of our emails are HTML paste. After creating the email in Content Builder and then close and reopen, we're noticing large blocks of the code highlighted in yellow. These emails have worked great in Classic -- Return Path and Litmus tested, as well as, live testing. Does this mean there is an issue with the way the code works in Content Builder? This is a difficult transition for us based on the complexity of our sends. Any tips or advice would be greatly appreciated.