Andrew Sperry

yes it appears in 0.12.2

Image one shows the group of spider mobs that the harming potions are used on.
Image two is directly under the mobs after killing them with a few splash potions of harming.
When killing them by punching, image two has tons of item and exp drops waiting to be picked up. Potion kills just dont yield anything.

I did not disable anything. Make a spider trap and then throw two-three harming potions on the group of mobs and they die but no items or exp drop. If I spend 30min killing the mobs by punching them, they drop items and exp just fine.

I noticed this same thing but I believe it may be that when a user logs out and back in, the mobs respawn in a slightly different spot. I had a 3x3x3 room with creepers in it, glass sealed all around after logging out and then back in one would be outside of the sealed area in my fortress.

I can confirm this on Windows 10 Beta Edition. It's very annoying and discourages the use of splash potions all together. They also don't drop items when killed by splash potions.

Windows 10 edition

I have found so many empty mob spawners, especially in abandoned mineshafts and the nether. I have 250+ hours of play in my world and when I visited the nether and found the close fortress, every spawner was just an empty cage and their was also no chests to be found anywhere. No blaze or wither skeletons either.
After a few weeks I traveled for ages in the nether and found another fortress. This one had chests and spawners. I think because I found it after the 0.12.1 update, it was working. Its just such a hassle that it is so far away. Running takes like 5-10min just to get there while the defective fortress is like 30 sec away.

I have also visited 10-12 underground mineshafts and all of them have had empty spawners (poisonous cave spiders) and no chests. I have literally spent weeks looking for melon seeds but since every mineshaft I visit is damaged I cant seem to find any melons or melon seeds anywhere. My map is almost 400MB and I havnt found a jungle either.

Im hoping that their is a feature implemented where the user can refresh a seeds spawners once they get fixed without disrupting everything that has been built.
Maybe a feature can be implemented in the menu that will refresh a seeds mineral deposits and spawners but the feature can only be used once a month or something like that. Even if it is only a one time thing when the beta is over I would be good with that. I really like my seed and have spent 250+ hours in it, the broken spawners and and glitched mineshafts just take the fun out of everything.