When sing any redstone in 14w25a the tick rate is extremely slow and takes about 2 seconds on non-delayed repeaters also when using pistons block updates are extremely slow and the blocks being moved dissapear for a few seconds it like only one redstone thing can be on at a time.
these are not noticeable in pictures but if you try in your game you will see
Picture 1- The red stained clay on the right is quartz but the lag made it lok like that for a while
Picture 2- I've been off the pressure plate for about 10 seconds and its still open
Picture 3- After 4 seconds of sitting the power still hasn't gone through a one tick repeater
Picture 4- Same as picture 3
does not appear for me anymore in 14w25b