If you activate an observer by updating him, then start moving the observer while it still gives out power, and then reload the game before the observer finishes moving, then the rotation of the observer will change.
If the output of the observer was facing into the +y direction, he will rotate to face into +z.
If he was facing into +z then he´ll face into +x.
If he was facing into +x then he´ll face into +y.
Same happens with negative directions. -y goes to -z. -z goes to -x. -x goes to -y.
Here´s a video demonstrating the bug:
https://www.youtube.com/watch?v=qFKHRlapufQ
Linked issues
Comments 3
Seems to be a dupe. Will reopen MC-108054.
If this bug report ( MC-108695 ) is considered to be a dupe of ( MC-108054 ), then I will heavily edit that bug report ( MC-108054 ), because there are the following differences between the two bugs:
1. Since 16w41a it´s not enough to move and reload the observers to produce the bug. You need to update them first, otherwise the bug doesn´t occur.
2. /setblock commands work fine in 16w41a
3. Since 16w41a observers now don´t always rotate towards +z anymore, but they also rotate towards other directions,
Basically I will have to rewrite the entire MC-108054 bug report, and I thought it would be more logical to just submit a new bug report for this. But I will just copy paste what I´ve written here into MC-108054 if you want.
Relates to MC-108054