so to begin with, here is some information

Game Version: 1.2 (323307)
Language: english
Modifications: none
Game Start: The Young Gun
Situation:
I bought a mining ship (Magpie WEV-014, can be found in the save game), with a captain and one service crew member, and ordered it to fly into my current system with the "unknown station". I than turned "AutoMining" on and set the Gate Distance to 0 (zero), but it is being ignored.
Settings the Gate Distance to 1 works as intended - the ship only travels 1 system. But setting it to 0 lets the ship go as far as it wants.
Expectation:
Setting the Gate Distance to 0 will keep my mining ship in the current system and won't let it travel anywhere else.
Results:
With Gate Distance set to 0 (zero) my mining ship travels anywhere it wants to.
Download: x4: Foundation Save Game File (Google Drive)