The game client renders fleets in the zoomed in tactical interface even while they are still in transit to a world. For starship fleets which travel at 0.2LY/watch, they are visible (and targetable) in the planet view for a few minutes before they actually arrive, and their status is still "in transit".
This is problematic because players can order an attack on these fleets, which do not fire back due to the "in transit" status effect. Essentially, any starship fleet a few minutes away from arrival can be destroyed for "Free" by a player who has a fleet in orbit of their destination world.
This was discovered in a late Era 3 war involving TheBugKing and myself against Wayward Device, both of whom can therefore confirm the existence of the bug/exploit.
It is partially fixed if Era 4 starship speeds will be increased to 1LY/watch as suggested by some in the forums, however the underlying issue will still be present and will affect any future slow-moving ships/fleets (constructions?)
The game seems to treat any fleet <1LY from a planet involved in a movement order as being in orbit of that planet, and appears to calculate fleet position in real time even though the galactic map does not show this. Fleets stop being able to use their weapons while "in transit"- I believe this starts either at the instant that a movement order is issued or at the beginning of the watch after the one in which the order is issued . When departing a planet, they appear to remain in orbit and can be fired at by other units until the end of the current watch plus the time that their speed would take them >1 LY away from the planet. For jumpships this window of vulnerability is no longer than 1.2 seconds. Starfrigates and starcruisers would appear to take up to 5 watches to leave orbit. Crucially, the same is true for fleets arriving at a planet, although they do not seem to be treated as being in orbit until the beginning of the watch after the one in which they get within 1LY. A fleet cannot use its weapons until its “in transit” status clears, but can be attacked from the instant that it is treated as being in orbit.
Some departure lag is fine and should be retained, it is a good mechanic because it forces fleets into decisive encounters rather than allowing players to retreat them immediately if an enemy brings in jumpspeed reinforcements. However, long windows of vulnerability on arrival are definitely not a good mechanic.
Interestingly it appears that transit time is calculated from the moment that a command is issued, and not from the end of the watch as I had previously believed.
I support adding an Era 4 tag to this issue.
Agreed, this is tied to an exploit and should be addressed ASAP
Fixed in Era 4.4. Unfortunately, I could not easily retain the delay when leaving—both are linked in the code.