Version Information

Minecraft version: 1.12.2
Forge version: newest
Other mods (if applicable):
AdPother-1.12.2-1.2.11.0-build.0557.jar (Pollution Of The Realms)
ForgeEndertech-1.12.2-4.5.4.0-build.0534.jar
CubicChunks-1.12.2-0.0.1055.0-SNAPSHOT-all.jar

Steps to reproduce:

1. Go to Pollution Of The Realms config and change "GlobalEmmisionsRate" to 1000%. This will make things easier to see.
2. Go above 255 blocks and place furnance in closed room.
3. Make furnance smelt something for example wood to charcoal.

Expected Behavior: Pollution should stay here and cumulate.

Actual Behavior: Pollution disappears after a very very short amount of time may be even milliseconds.

Some other info - You can place pollution block and it will work normally, machines just cannot generate it somehow. It may be AdPother fault because of that i reported it to AdPother author. For now no respond. If You need more details Barteks I am KubiRemPL on Your's discord and can speak Polish as You can.

It would be so cool if You can fix it.
Thank You!!!
KubiRemPL