I'm remembering past cases of a broken return spring, but don't have the details. Here is one case (which doesn't match the thread title): Gear Shift Keeps Returning to N | PriusChat If you can't find other descriptions with the Search function, then try sending a private message to Patrick.
No, plug and play. Easy job to do. There are videos on YouTube that shows you how to change the MFD screen and that pretty much covers disassembly of that lever too