Consider a block that has 2 or more redstone torches attached to it. If a 2 tick pulse is sent to the block to power the torches off, some of the torches will turn off for two ticks as expected, but others will turn off for one tick.

There will always be at least one torch that turns off for 2 ticks. Occasionally (in some versions or orientations of the circuit), two of the torches turn off for 2 ticks. The torche(s) that turn off for 2 ticks will always be the same ones unless you change the circuit.

Often, it can depend on seemingly unrelated things upstream such as the orientation or position of the 2 tick generator (either a standard torch + repeater design or just a 2 tick repeater with the player quickly placing and removing a power source)

If the block only has one redstone torch on it, it will always work as intended. Adding another torch can affect the behavior of the original torch. As you add more torches, you find that torches on certain sides of the block always take precedence over others (the torch on one side of the block will always be the one that turns off for 2 ticks versus one on a different side. B > C > A > D) But if you rotate or change the circuit, it will be different.

A simple way to recreate this bug is to place a 2 tick repeater pointing into a block. Place a torch on the left and right side of the block. Place two lines of 1 tick repeaters being powered by the torches, one line for each of the two torches. Quickly place and remove a redstone block to power the 2 tick repeater for 2 ticks. Pause the game and you will notice that one line of repeaters has 2 repeaters off, while the other only has 1 repeater off (indicating one line was briefly powered off for 2 ticks, the other for 1 tick)

You can also have the lines of repeaters power two redstone torches at the end. Since a torch only turns off for a pulse that is 2 ticks or longer, only one torch will turn off.

Pictures of this setup and its operation is included in the attachments.