The bug

Take a redstone circuit like depicted in test_setup.gif. You will observe, that the output of comparator receiving the alternating redstone signal won't be the same depending on its position which you can see in comparison.gif. Note that this behavior is only induced when the comparator of interest is facing south and receiving the redstone signal directly from a clock. Indirect signals will always be transmitted by the comparator no matter its position like you can see in indirect.gif.

Expected Behavior

All comparators no matter their position transmit the signal just like in the bedrock version of Minecraft or like after an additional comparator in between (indirect.png).

How to reproduce

1. Create a new void world
2. place a comparator facing south (south facing comparators output their signal to the north) at 0 4 -1
3. directly connect a redstone clock alternating between redstone strengths 14 and 1. (test_setup.gif)
4. repeat steps 2-3 with a comparator at 5 4 -1
5. observe the different comparator's reactions/output to the clock

A demonstration video is up on https://youtu.be/ERT-WmMwYHY

Imagery

If we plot the positions of the different behaviors you can observe striped/diagonal patterns. These patterns change approx. every 67th block on the z axis.

Some images depict responsive (white concrete) and unresponsive (black concrete) positions. A comparator at a responsive position transmits the alternating signal, an unresponsive comparator doesn't.

Images:

• pattern_at_0_0.png: The purple block in the center of the image shows the coordinates (0, 0), the red block the positive x direction.
• irregularity.png: This image shows an irregularity like described in Disclaimer.
• indirect.gif: The rightmost comparator was placed on an unresponsive position.
• test_setup.gif: The rightmost comparator was placed on a responsive position.
• comparison.gif The upper rightmost comparator was placed on a responsive position; The lower rightmost comparator was placed on an unresponsive position.

Datapack

We used a datapack to identify the responsive and unresponsive positions. The zip is attached as BugTrackingPack.zip. To generate the images run the command in a void world with the datapack enabled:

/summon minecraft:armor_stand 0 10 0 {Tags:["anchor"],NoGravity:1b}

also make sure to run /gamerule doTileDrops false

Notes

We still don't know everything about this bug and thus not every information is guaranteed to be correct. Things we haven't fully explored yet:

• north facing comparators
• different heights, we only tested on y=10
• different redstone strengths, we only tested 14/1
• irregularities in the transition of patterns like shown in irregularity.png
• border widths of patterns
• versions below 1.13, This is the lowest version we tested since our testing datapack only works in 1.13+.