Any time I create a Void World (Superflat with preset 1;0) Redstone runs in slow-motion. I'll press a button, and it'll stay pressed for about 5 seconds. Hoppers transfer items once every 5 seconds-ish, signals don't update for about 5 seconds, everything is in slow-motion. Maybe chunks aren't updating due to no land? It works fine on Default worlds...
Environment
A Superflat world created with the custom preset of 1;0 or 2;0;1
i have this in standard flat world using: redstone, redstone repeaters and buttons.