Hello,
at first, I tested alot with the problem that I found. And finally I think its something with WCT, but im not sure.

So, you can see in the picture this spamming "Redstone work" and a single "No network power", my AE2 Core is in the spawn chunks just like the command block with the "Redstone work" signal. The power for the command block is a AE2 redstone p2p tunnel, that means: AE2 Network run -> "Redstone work" work, but not the WCT. (the whole day it worked good, but since a random time, it stopped working)
(I am in a custom RFTools dimension)

Maybe the AE2 redstone p2p dont update oneself, in spawn chunks, the issue is not at your side, then sry.

Fun fact: Only with an external chunk loader OR with the creative AE2 energy cell, the connection work.
My energy producer are always loaded (also in the spawn chunks)

Minecraft: 1.12.2
Forge: 1.12.2-forge1.12.2-14.23.3.2670
AE2stuff: -0.7.0.4-mc1.12.2
AE2: appliedenergistics2-rv5-stable-11
LIB: p455w0rdslib-1.12-2.0.29
WCT: WirelessCraftingTerminal-1.12.2-3.9.64

If you have an Idea, why this happend, pls tell me. :D