I just installed the latest Beta on my FireStick Lite. I never had the BEta installed on this stick before, and my other FS are all 4k. It seemed to install okay and seems to work okay, but the app icon for the Beta on the FS Lite home screen is just some sort of grey default icon that it appears to use when it has no real icon to use.
I have the same thing on my FireTVCube you have to wait until it is officially released.