The ENTER_ZONE_dock event no longer appears to be firing for my linux client and it breaks one of my plugins functions (dropping cargo at the dock entrance).

Is this a permanent or intentional change or a bug?

That event appears to be working fine for me, and I also run the Linux client.

Event: MSG_NOTIFICATION - Data:
           1: (string) "Press the Activate key to dock."
           2: (number) 5
Event: ENTER_ZONE_dock - Data:
           1: (string) "dock"
Event: LEAVE_ZONE_dock - Data:
           1: (string) "dock"
Event: MSG_NOTIFICATION - Data:
           1: (string) "Press the Activate key to dock."
           2: (number) 5
Event: ENTER_ZONE_dock - Data:
           1: (string) "dock"
[Sat Apr 13 00:31:23 2013] People in the room: draugath
Event: ENTERING_STATION - Data:
Event: HUD_HIDE - Data:
[Sat Apr 13 00:31:23 2013] You are now in Ellias Stand (Itani Barracks).
Event: SHOW_STATION - Data:
Event: ENTERED_STATION - Data:

If you turned Auto-Dock on, that may be part of the issue (unless that was considered when the plugin was originally created), since Auto-Dock changes the order in which a number of events trigger.

[Sat Apr 13 00:34:44 2013] People in the room: draugath
Event: ENTERING_STATION - Data:
Event: HUD_HIDE - Data:
[Sat Apr 13 00:34:44 2013] You are now in Ellias Stand (Itani Barracks).
Event: MSG_NOTIFICATION - Data:
           1: (string) "Press the Activate key to dock."
           2: (number) 5
Event: ENTER_ZONE_dock - Data:
           1: (string) "dock"
Event: LEAVE_ZONE_dock - Data:
           1: (string) "dock"
Event: LEAVE_ZONE_NFZ - Data:
           1: (string) "NFZ"
Event: SHOW_STATION - Data:
Event: ENTERED_STATION - Data:

Must be some sort of timing issue then -
It worked before with docking on and off so I am not really sure why it is broken
I guess I will have to go back and see if I can figure out something that works

After some more investigation I think I understand the problem.

It appears that auto dock is initiated on the server instead of the client.
The server sends an Entering_Station event which is received before the client sees the ship in the dock area.
This does not leave enough time for the client to send its jettison cargo message to the server which thinks the ship is in fact docked.

Assuming the Devs Dont decide to install a one second delay which would fix this in most cases,
It looks like I need to shut auto docking off and then Dock the ship after the cargo is delivered.
... Now I just have to figure out how to turn auto dock on and off with in a plug in.....

Check the wgaf.cfg for a clue.

set Cvar might have been a bit more useful hint. :P

This is a case where the journey is as important as the destination.