Currently, an important tactic in war is capturing enemy jumpship yards to extend your own jumpship access to enemy worlds outside your sector capital control radius. This is because jumpship yards continue to project a jumpbeacon after they are captured, even if they are outside the control radius of a sector capital.
If your enemy has placed their jumpship yards within 250 LY of one another, it's possible to leapfrog through an enemy empire pretty fast as long as the yards aren't too heavily defended.
Consider if this is desired behaviour. If so, I feel that jumpship yards should continue to project a jumpbeacon for a couple hours after being redesignated. If two players are active and fighting one another, the player being attacked has a strong incentive to redesignate their jumpship yards as they come under attack in order to prevent their enemy from getting additional jump access. This incentivizes players to only attack empires whose players appear to be AFK and not to wage head-to-head war, which makes combat less thrilling.
If this is not desired behavior, then jumpship yards should not project a jumpbeacon when they are outside the control radius of a sector capital.
I also feel that jumpship yards should not project a jumpbeacon immediately after being designated. They should only project a beacon after roughly 24 hours have passed.