I've seen this happen enough times to finally write a post on the boards. So, I've encountered rengar in the top lane several times and it's cost me lane multiple times when he extends his jump range by walking out of the bush and then jumping and 100 to 0ing me with his empowered Q. This bug means that if I'm not playing a champion that can out trade him level 1, I have to basically sit at the start of the river to be out of range.
Here's some pictures to show you what I mean. They should be in order but if not they're numbered 1 to 6.
NOTE: I know it looks like when he first steps out of the bush his jump animation is playing but I've watched the replay in slow motion several times and can see that his walking animation plays for a solid second once he's out of the bush before he jumps.