Modpack version:
2.8.0

Java version:
1.8.0_292

Description:
Server crashed when adding 16 magical speed upgrades to a Mechanical user in the Aether.
The Mechanical user was connected to a fluid transposer, which was connected to an ender tank with lava (getting a lava bucket, placing it and returning it back in the transposer with a enderio filter), and next to them was an autobreaker.
Restarting the server kept crashing, since the chunk was loaded.
My guess is that the Mechanical user right-clicked a bucket on the aerogel before the autobreaker managed to break it.

Minecraft crash report:
https://pastebin.com/3v9fbW0j

duplicate of #395

Placing Lava in the aether is extremely unstable and frequently crashes regardless of what it used, and is informed of in the questbook. There is a MA recipe provided. Theres no fix other than "dont use it", sorry.
Duplicate of 395, as stated by johan.