Describe the bug

Attempting to connect a Mekanism mechanical pipe to an AE2 fluid interface causes an issue that causes the world to not load and crash on startup

To Reproduce

1. Place AE2 fluid interface block (Specifically the full block not the smaller interface that goes on the side of blocks)
2. Place a Mekanism mechanical pipe next to the interface block
3. Expect game to immediatelly crash and the world is now unable to load

Expected behavior

I expected the mechanical pipe connects to the interface with no errors.

Additional context

Forge: 1.15.2-31.2.23
Mekanism: 1.15.2-9.10.9.422
AE2: 7.0.0-beta.1

This isnt just a client side issue this also crashes servers and locks up the world.
https://pastebin.com/wMvtDVLd

Environment

• Environment: https://pastebin.com/Yah7ZMZK
  I've been having this issue running on a server but copying the world to singleplayer results in the same issues.

Going to comment here given an issue (mekanism/Mekanism#6408) was also opened on the mek repo though they were not linked. The issue is that in forge 1.14+, getCapability is nonnull, but AE2 is returning null instead of returning LazyOptional.empty(). On a similar note you (AE2) should not be doing what is being done a few lines above that (returning a new lazy optional every time getCapability is called); I recommend reading the JavaDocs on getCapability and LazyOptional#invalidate

Should be solved in next beta (see attached PRs).