The bug reporting forums are at
https://forums.frontier.co.uk/forumdisplay.php/124-Bug-Reporting
The game *does* filter these missions correctly as Illegal if you use the filter drop-down in the top left, so definitely a bug.
Yep. worth a bug report, but...
Back in the day, I also noticed that the filter didn't work for planetary scan missions. I suspect it's because whether they will be directed at a private beacon and thus entail an unavoidable trespass bounty is RNG, so no way to know whether it'll be illicit or not.
As for getting that bounty, IMO it's so trivial as not to worry about it. The missions themselves aren't really any more challenging if the beacon is private, you can typically do a bunch of them before you need to visit IF and clean your ship. I've been interdicted by system security when wanted with such bounties and was told everything was in order and have a nice day.

Just watch it when it becomes a superpower bounty (after doing five scans in a superpower's jurisdiction), as you tend to get NPC bounty hunters after you then.
