Player/Entity Lighting pops instead of smoothly transitioning

I've noticed what i think may be a small bug with the player/entity lighting. I was flying around a couple of torches, when i noticed that if i flew up just a single block (roughly), the player light level would jump from being fully lit, to not being lit at all. I checked the block light where my player was, and it was at 9. Not sure if this is intended or not, but it seems like a bug.

In fact, it appears like the player lighting goes to completly dark whenever the player isn't on the same Y level as a block.