GRUB_TIMEOUT > 0 also causes the vendor logo to be replaced by a black screen, but that seems to be Grub's fault. Default Ubuntu won't have that problem since it ships GRUB_TIMEOUT=0. And if you want a nonzero timeout without the blackness then GRUB_TERMINAL=console is a workaround.
GRUB_TIMEOUT > 0 also causes the vendor logo to be replaced by a black screen, but that seems to be Grub's fault. Default Ubuntu won't have that problem since it ships GRUB_TIMEOUT=0. And if you want a nonzero timeout without the blackness then GRUB_TERMINAL= console is a workaround.