The reason for the confusion is that it is normally specified that the shield should be connected to GND in both ends, but that is a bad thing in many cases.
One advantage with TP ethernet is that there is a galvanic isolation between the units. This isolation is destroyed if shields are connected to GND in both ends.
The risk is high for unwanted currents in the shield.
Different designers try to solve this problem in different ways.
If allowed, use unshielded connectors in your design! Shielded cables will work anyway, and the shield will help a lot even if it isn't connected to anything.
If unshielded isn't good enough, use a fiber-optical solution.