bones refreshing trouble

Hi,
I’ve spent a lot of time making a rig for my character and finally everything seems to work fine except one thing. Bones follow others in correct way, but when I run test animation in viewport I noticed that some of bones (with connected parent) are left behind - they are moving slower than others but finally finding themselves in correct position. I thought thats just performance of cpu and it won’t be noticeable in rendered animation. I was wrong, render was exactly like viewport version. Is there some option in blender to solve this?