So I guess it was one of the most recent updates that changes how machines work with BC/RP but it broke my autoreloader for my geothermal generators. As it is now you can only put and get things from the bottom slot of the generator from the bottom side, which doesn't sound so bad until you realize that you need to both put buckets in and remove the empty buckets.
As such I would suggest that you would be able to access the bottom slot of the geothermal generator at the very least (not sure about other machines) from both the bottom and the sides.
The other alternative would be to have an output slot in it that empty buckets go to once they've been emptied that can then be pulled from the sides.