Not a huge deal since I can always keep booting 4.0.4, but I do hope they figure out what is going on, and fix it.
Protip: Since I am gaming/gamedeving, I need video drivers to work, and on the MBP you HAVE to boot/install from BIOS mode and not UEFI mode if you want things to work well. Also, that whole experience of trying every distro known to man on the MBP made me hate apples weird u/EFI setup, and UEFI in general.
/gimme bios back!
Yes, please do hate Apple's garbage EFI implementation, maybe someday they'll actually get the hint and release UEFI compliant firmware. I use UEFI daily on four different systems in my house (Lenovo W540, Surface Pro, XPS 13 (2014), custom-build desktop) with no issues, but god help you if you try to boot anything but OS X on a Mac without using BIOS Emulation.