Items in hoppers and redstone signals duplicating

I have a continuous circle of hoppers with a single item in the circuit (to simulate a timer) when I leave the world, however, when I enter the world again, there will be two items (a duplicate of the first one) in the circuit of hoppers, both of which send a signal through a comparator. This has been a problem in several versions and in several worlds.
Also, the same thing happens, but with a redstone signal in a continuous circle of redstone and redstone repeaters. There will be a single signal going through the circuit before exiting the world, but when I enter the world again, there will be a second signal following the first.
I have tried reinstalling Java and Minecraft and it has not changed the nature of the bug.