Versions used:
IndustrialWires (any version beyond 1.7-26 (1.12.2)
Forge 2854
industrialcraft-2-2.8.188-ex112
VanillaFix 1.0.10-99

If the dedicated server shuts down, upon unloading chunks, industrial wire connections will be marked as removed and will have to be replaced to start transferring power again.

(this is also sometimes reproducible by unloading the chunk by going outside the loaded chunk distance that the connection is located in, not recommended to try and reproduce with this method.)