Description of the issue:

After upgrading dedicate server and client from IE 4.2.4 to 5.0.5, the server start to crash. The world loads normally, but once some player joins, it crashes and says

java.lang.RuntimeException: Unexpected direction: down
        at blusunrize.immersiveengineering.api.utils.shapes.ShapeUtils.rotate(ShapeUtils.java:36) ~[immersiveengineering:?] {re:classloading}

Crashlog:

crash-2021-11-15_04.36.45-server.txt

Versions & Modlist

Forge 36.2.9
IE 5.0.5 (Originally 4.2.4, just updated and loaded same save)

It is impossible to load the same save with other mods deleted - that will ruin everyone's day in the server (cuz all blocks will be gone)
However, testing it in single player with only IE will still cause this crash if any downward facing Structural Arm is placed when using IE 4.2.4 and then loading up the world again with IE 5.0.5, with exact the same stack trace.

However, testing it in single player with only IE will still cause this crash if any downward facing Structural Arm is placed when using IE 4.2.4 and then loading up the world again with IE 5.0.5, and then some entity come in contact with it. The crash is with exact the same stack trace.

My personal interpretation is that this is a bounding box issue with the structural arms.

Also, this is what at the problematic coordinate reported in the crash report:

(Screenshot taken after loading the server up with IE 4.2.4)