I've had this problem for quite some time, but gave up months ago when nothing worked (rebuilding cache -upgrading to latest version of postgressq etc etc) I thought it was just with some of the premium huds that I bought but when I started using a copy of the default tournament HUD it also crashed, it just crashes on Spins and not in regular sit n gos.
It usually saves one or 2 or sometimes even more changes but eventually clicking save layout no longer works, there is no error message, the only indication that I have that something has gone wrong is when I click on Stop importing hands and I have to close PT4 via Task Manager.