This isn’t new to 4.8, but it’s been bugging the heck out me for ages.
The running animation (create a new Third-Person project, C++ or Blueprint), isn’t actually smooth. As it gets to the end of the animation, the animation ‘snaps’ to zero time. Once you notice it you can’t stop. Changing the velocity of the character to match the animation doesn’t seem to have much effect either.
It’s meant to be an animation to prototype your game, I guess that makes it OK if it’s not perfect! 
The sooner you’ll integrate your own the better anyway!
Hi guys,
This is a known issue with the run animation and in fact was there in the previous versions. The new mesh makes the “pop” more obvious. We have a bug report for it, but the fix required an animation change that was put off until past 4.8. Unfortunately, the “pop” will be there for 4.8 as of right now.
Cheers!
Cool thanks ! Just wanted to make sure it’s on the radar