Lighting Bug After Optimizing World.

I was was walking in my cave after i optimized my world, and i tried to update the blocks but it stayed the same way (Look at Screenshot)
 
What I expected to happen was...:
When i go trough my cave, my light should look like normal not like i'm playing Alpha minecraft 1.3. Even when breaking the block, and replace it with another one, the light bug stays the same.
 
What actually happened was...:
Smooth light broken, it does not update. Even when restarting the world.
 
Steps to Reproduce:
1. Make an world everything before 1.14 Pre Release 3
2. Make an cave or whatever like mine. Dont Forget to light it
3. Upgrade to 1.14 Pre Release 3 and optimise world before loading
4. (I think it has to do with the optimise button, dont know it does not without it)
5. See if the light is broken now