Mobs spawning on glass And well lit areas.

Slime spawning below level 40 (second and third screenshots) are intentional - assuming you are in a slime chunk. They will spawn even in well lit areas (light doesn't prevent slimes from spawning in slime chunk). Use lower slab floors to prevent them from spawning.

The slime pictures were taken in ocean biome. Are they normally supposed to spawn there? Will the slabs also keep them from getting stuck as well? What about the other pics I sent in as well about the rest of the mobs?

Same at my home. Nintendo Switch, 1.9

Can confirm. I've been having both hostile and non-hostile mobs spawning in and around my house both well lit and built completely out of wood and polished andesite as well as glass. Everything from cows to creepers surprising me in my house. 

Windows 10 Edition, Version 1.9 btw

I'm having the same problem with creepers and skeletons showing up in areas of my well-lit mine and underground storage areas, with torches every 6 blocks. 

I'm also having a crazy abundance of slimes spawning in multiple areas of my mine and the surrounding caves, all well-lit areas. Please don't fix this part, as I actually like it. LOL.

Please confirm.  We are experienced Minecrafters and can confirm this problem on the Xbox one.  The inability to keep specific areas safe is practically game-breaking (e.g. villagers keep being killed).  We can also confirm spawning issues with both hostile and passive mobs.

I have not seen this in person although it was reported to me in 1.9. I had a creeper in my storage room on 1.10 but technically he could have wandered there instead of spawning. 

I am writing to state that at times in the past, lighting has not crossed chunk boundaries so that, for example,  if a torch is near a chunk boundary it may look well lit but the game doesn’t count the torch light on the other side of the boundary. 

In one area of the map it was lit every six blocks, in a grid.  In another, it was lit every four, also in a grid.  This should not allow hostile mobs to spawn.  Collectively we have logged tens of thousands of hours and can say with confidence this is a new bug.  Perhaps there are dark areas underground and the change in coding is allowing them to spawn at the surface level instead, but that doesn't explain passive mobs spawning in off-limit areas or slimes spawning in the wrong biomes.  No, this needs to be fixed.

On Windows 10 and version 1.10 I've had this happen where drowns are spawning in a well-lit terracotta pond lit with sea lanterns in walls and floors.

This is constantly happening, I have a big city that is getting ruined by the look of torches everywhere, mobs still find spots to spawn somewhere even though there are no dark spots and I have a light source every 4 or so blocks, which shouldn't even be required

Still having the same problem in 1.10. Torches both on the ground and wall 6 blocks apart and still getting creepers and drowned popping up and ruining my builds. I literally just started this world last week and i've already had to patch up 4 well-lit areas after surprise creeper attacks.

In my Realm I have a field I've flattened for a perimeter 8x8 chunks and entirely covered in carpet. Hostile mobs still spawn on it. Not many and not often but they do. All types.

This is still happening, been playing about 10 days now, and mobs spawn outdoors regardless of the amount of torches, even if their only a couple blocks apart. I also get bats in my house (no mobs though thank goodness), even though I'm at sea level, and have only a 7 block high house that is very well lit.

Is this still an issue for anyone in 1.14.30 or later?

I'm having this issue on ps4 1.14.41 I had a creeper spawn right in front of me in a well lit cave then 3 zombies as soon has I took out the creeper.