Adjacent BeltSorters don't work

You must always place one normal belt inbetween two beltSorters. BeltSorters are only able to place items and don't have an inventory, therefore they can't connect to each other.

BeltSorters appear twice with the same name in the energy statistics

Yes this is on purpose. The BeltSorter is actually a lamp entity without light. That way it allows to set a condition when the BeltSorter should be running. However when you don't set a condition on the lamp it usually deactivates during the day. Therefore every placed BeltSorter adds another hidden lamp which sets a condition that is always true in this case. Now depending on whether you set a condition on the BeltSorter or not, one or the other lamp is active and consuming energy. Therefore you get to see two BeltSorters in the energy statistics.