Strong lag in Super Flat worlds

Well , since 14w26 was created , i made new Superflat world and Everything has Move delay , except for me. Well the delay was 1 single move of INCH for 0.5 seconds. This continues also in 14w28b. I dont have an explanation. ill try find info.
The items isnt lagging when dropping , but trying to pick it up tooks 1 , 2 or 3 seconds of normal.