xJon/The-1.12.2-Pack#982
Java on local PC:
java version "1.8.0_381"
Java(TM) SE Runtime Environment (build 1.8.0_381-b09)
Java HotSpot(TM) 64-Bit Server VM (build 25.381-b09, mixed mode)

Java on Server:
openjdk version "1.8.0_422"
OpenJDK Runtime Environment (build 1.8.0_422-8u422-b05-1~22.04-b05)
OpenJDK 64-Bit Server VM (build 25.422-b05, mixed mode)

Affected mods:
thaumictinkerer-1.12.2-5.7.1-Unofficial.jar
cfm-legacy-1.12.2-6.5.0.jar

Issue is repeatable in both SP and MP

Whenever i come close or look at a "Dark Oak Upgraded Fence" or "Dark Oak Fence" while wearing the "Leggings of the Burning Mantle", the fence visualy connects to anything on all 4 sides - even to air.
For this to happen, the characters head has to be on the same level as the fence and in at least 6 blocks of range.
Tried also without the enchantment - same behaviour.

This visual connection is also only temporary leaving the visible range and returning reverts the visual appearence back to normal.

short video #1
short video #2

They are probably connecting to the Nitor Vapor?

    # Can Energetic Nitor and Kami Leggings glow
    B:"Enable Nitor Vapor"=true

fixed