this last Nation War I noticed that when ships are in the undock animation coming out of tridents they are invulnerable. This cause me to not kill a few people as they undocked (or at least take half their health) I landed a good half a power cell's worth of LENB fire on one ship with no effect, and I know lag wasn't an issue.

This is intentional, similar to how you're invincible during the first couple seconds after you jump into a system. It applies to undocking from stations as well. Note that while invincible, you also can't control your ship, so it's not like you can take advantage of it to shoot at people without repercussions.

If you don't like it, make a suggestions thread.