In All The Mods v.1.60b as far as I tested generators using normal fuel and liquid fuel generate energy to adjacent TechReborn machines without using any fuel.
In fact you can just put the machine right next to a generator that never recieved any fuel and it will instantly be full of energy and stay full while processing items. Works from all sides (have not tested top or bottom however).
Connecting the machines with cables however works as intended.

RELATED ISSUES:

#1037 - 1.11.2 Generators produce power without the need of fuel

NOTES:

• People on #1037 discovered this does not happen when TESLA is not installed.
• https://pbb.lc/daten/techreborn.gif
• See #1037 for more info