So I updated everything to Horizon View 7.7 (Connection Server, Agent and Client). PCOIP still displays the black screen, for approximately 15-20 seconds but then it renders. With Blast the black screen persists and the user is required to press enter to acknowledge the invisible disclaimer screen.
Either way this is unacceptable for users. We won't go into production with this. If I cannot get a fix we will I guess have to move the disclaimer to the underlying OS.
Horizon View 7.7.0
Connection Server 7.7.0-11038474
Horizon Client 4.10.0-11021086
Horizon Agent 7.7.0-11054235
Nvidia Grid P4
412.16 Drivers
Window 10 1803 Release