After looking at the community, I learned that there is an issue where members of the redstone community are experiencing dissatisfaction. I've done some research, and I have come to the conclusion that the only way to fix this issue is to change the copper bulb to have a 1-game tick delay as it had before.
I've also done some research, and I have come to the conclusion that this is not a bug, but feedback. See MC-266742 for more details.