Is there a branch where this code change can be reviewed?
The intent of bug 1412 was not to break spec alignment on the uefi defined protocol and SetMode() function. We had a proposed change that can be seen here. https://github.com/Microsoft/mu_basecore/pull/13/files
The idea was for new devices published, only clear the screen if the mode needs to change. Our reading of the UEFI spec didn't define how new devices needed to be added and didn't require the screen be cleared.