block lag

Is fixed with the new snapshot 15w39c

I have a block lag problem. I started a survival world on 15w38a and everything was fine. But since i upgraded to 15w38b i have a block lag,in survival i need to break a block 2 or 3 times and in creative a block has a break delay of 4 seconds this is also a problem in 15w39a and 15w39b.
when i wrote this 15w39b is the newest version. I tried to set the video settings to minimal but it doesn't work, I used to play Mc normal. I also play modded survival with 40 mods and i have no problems. My FPS is 40
in attachment is the game output and the crash report when you press F3+C