A comparator should always have a 1 tick delay no matter what's powering it.
Comparators that appear to be activated, but actually aren't, will in some cases have a delay of 0.5 ticks. This happens when they are powered by another comparator or a repeater. However, the delay is 1 tick when powered by a block or a redstone.
To reproduce this bug:
1. Set a comparator to subtraction mode.
2. Power rear input.
3. Power side input with the same signal strength as you used on the rear input.
4. Turn rear input off.
5. Turn side input off. The comparator should now look activated while receiving no input.
6. When this comparator gets powered by a repeater or another comparator, the delay will be 0.5 ticks.
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Related to MC-56084?
Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases. If this has been done, we can reopen the issue.
Keep in mind that the "Resolved"-Status on this ticket just means "Answered", and that we are waiting for further information on whether this issue still exists or not. We will reopen it as soon as the requested information has been delivered.
Is this still an issue in the most recent versions (currently that is 1.10.2, or 16w42a) of Minecraft? If so, please update the affected versions and help us keeping this ticket updated from time to time.
Can confirm for 1.12.1
Related to MC-12211
Is this still a issue in the latest version of the game(currently 1.13.1)?
If so, please add it to the affected versions, thanks!
Can confirm for 1.14
the timings for the comparator is not 0.5ticks
every second comparator is instant
If the comparator is in the 'bugged on state' and recives a block update (from redstone, repeater. comparator, torch etc) it will schedule a tile tick on itself, even if it shouldn't (the block update came from the comparator behind it)
The repeater turns on, the comparator revices the tile tick after the repeater (but in the same tick) and turns on, making it appear instant
This report looks similar to earlier reports of comparators looking activated despite not receiving an input, but this is not a duplicate as I am pointing out the timing issue this causes. The bug makes it much harder to synchronize redstone creations with comparators in them.