Found more about this
on the official forum:
Sandro Sammarco (Lead Designer) wrote:Hello Commanders!
Some feedback to help understand what may be going on!
There is a bug at the moment, I'm not entirely sure but I think it's more or less 100% reproducible: you are clean in a location that has an authority presence (basically, not an anarchy) and a ship attacks you and hits you at least once.
What *should happen*:
The ship is insta-basic-scanned and you are free to retaliate without penalty - after all, your ship now has confirmed status that the attacker is wanted (regardless of previous criminal status, the definitely committed a crime when they attacked you).
What is *currently happening*:
Your ship interface is lying to you. When you target the ship after it hits you, it shows a wanted status. But under the hood, the game is still waiting for you to complete a basic scan, which takes several seconds. If you retaliate before this scan completes, the game thinks you attacked a ship without knowing its criminal status - which is a crime, so you get a bounty.
We have detonated this bug internally - it should roll out in a future build.
Now, I know some folk will take issue in the fact that you have to wait until you are hit before you can retaliate. We do it this way because it gets complicated to try and work out if someone is attacking you when they have not yet hit.
Note this has nothing to do with KWS use. The KWS reveals additional bounties that a target has - it does not confer any right to attack.
The best way to think about this: faction A and faction B do not care about each other's laws, only their own. So if a target has a bounty for faction A, but is flying in space controlled by faction B, I can use the KWS to see the bounty and kill him to get a claim for it, even though I would be breaking faction B's law.
A note about "report crimes against me": if you turn this off, folk can attack you with impunity, as no crime will be reported. The main reason you would want to do this is if you don't want the police to turn up (for example, you might be clean at your location, but carrying a lot of stolen goods).
Makes better sense that way.