I get the same issue even if the chunk is loaded on remote side. Dialing is fine, wormhole is established and then 1sec later the gate close itself.
So I'm definitely thinking it's not a SGCraft fault since I can use nexDHD without that problem.
And I can replicate the bug 100% of the time, it's not random.
*** EDIT ***
Ok after some more test it seem that your program is interfering with other program that are connected to the same stargate.
I wonder why since I was using nexDHD and ccDHD without any problem. But as soon as your program is managing the stargate it prevents other program to work properly.
And the reasons behind why I do this is simply because every programs have unique features that I need/like from each.
Anyway would it be possible also a feature to export/import the addresses with a floppy?