When I converted my singleplayer world from 18w16a to 18w20a/b and + , all stone (and solid blocks) pass light through.
blocs dosen't stop light
Ice forming underground
phantom mob spawns when player is underground
Mobs burn under solid blocks in worlds ported from 18w16a
Stone, cobblestone and sandstone are all transparent after upgrade 18w16a to 18w20b
Mobs stopped spawning, until in new chunks and skeletons and zombies burn inside caves
Undead mobs burn in the day under blocks
Solid blocks don't protect undead mobs from sunlight
The entire underground chunk I load into gets lit up as if sunlight is reaching it
Mobs only spawn undergound during the night
Undead mobs burning underground in superflat in pitch black darkness
Deep cave light bounce bug
Zombies burn in caves. Lighting broken.
Underground areas are lit by the sky when upgrading from 1.12.2
Zombie is on fire even if there is a block which was placed in 18w16a above the zombie.
wrong behavior of mobs burning in daylight
Blocks underground still receiving sky light
Random Underground Spaces Appear as Light Level 15
Lighting anomalies when converting world from 18w16a or earlier
Mobs Fire Under Block Some Times
Zombie burn under ground
Mobs spawn extremely rarely when updating a map from 18w16a to 1.13-pre2
No spawn near spawner
Witches do not spawn as frequent as they should in witchhuts
Endermen do not spawn in the end.
In the cave, as bright as the outside.
Mob spawning still bugged
Light Levels do not seem to be corect in Villager Farm
Bug in caves
sunlight passes thru the ground
Sunlight in covered areas
daylight passes through blocks in my world in 1.13
Sunlight exists underground despite there being no possible light source
Sky light levels underground too high (since 18w05a)
Maps get filled with gray areas instead of revealing terrain
Hostile mobs don't spawn after upgrading from 18w16a
Aquatic mobs spawn extremely rarely when upgrading from 18w16a