i have this same problem.
I just made a fresh installation of Joomla 3.14 stable.
I use the latest framework version 1.40.
All changes to the layout are not saved, also the "!" icon warning remains there.
Also I have the impression that the POP UP for the save dialog is only partly displayed.
It is sitting just under the menu bar and looks cut in the upper part.
In case it helps, I use isis as the Admin template, language german/english (no change, whichever I use)
I'm having the same problem here. Fresh install Joomla 3.1.4 cannot save or clone any template Layout. Also after running "Compile Less to CSS I keep getting error " Unexpected error. Please refresh the page try again later.