Also having this issue:
Just tested some rounds in my map
All Cinematic Sequence Devices work correctly on round 1
They DO NOT work on rounds 2,3,4
They WORK on round 5
They DO NOT work on rounds 6,7,8
They WORK on round 9
They DO NOT work on rounds 10, 11, 12, 13, 14, 15
They WORK on round 16
It seems totally random whether or not the devices will work.