Missing Permit/Insufficient Jump Range course plotting issue - advice gratefully received.

[Joe Cool]

I'm a little over 350Ly from Sol, not exactly in the black, but above the central plane and systems are starting to become a little more spread out.
I'm running a PCII with a laden jump range of 26.68Ly (unladen 37.73Ly, but currently rocking a load 1232t of steel).
I'm attempting to plot the 157.39Ly back to my Fleet Carrier.

I'm plotting with USER DATA/VISITED STARS/NOT VISITED set to attempt to pick up those systems I may have missed on previous transitions.
If I plot FASTEST ROUTES I receive a ROUTE UNAVAILABLE (MISSING PERMIT) error.
If I plot ECONOMICAL ROUTES I receive a ROUTE UNAVAILABLE (INSUFFICIENT JUMP RANGE) error.
If I switch off USER DATA/VISITED STARS/NOT VISITED route plotting occurs correctly as expected.

Searches (3rd party tools) have revealed no evidence of any local permit locked systems.
Do I actually have an unknown locked permit system lurking somewhere nearby (exciting and any pointers on how to locate it would be great)?
Have I just bumbled into an area of the game with dodgy & misleading error codes (expected, that's what these blips usually prove to be)?

Should I just switch of the NOT VISITED filter, abandon further investigation, smile and carry on with my journey?

I thank you for your thoughts and attention on this matter of purely personal importance

 

[Neilski]

I'm plotting with USER DATA/VISITED STARS/NOT VISITED set to attempt to pick up those systems I may have missed on previous transitions.

An unusual problem (or at least not one I've hit). You're pretty close to Sol, indeed.
If you fly with that filter a lot (and in that particular neighbourhood), is it conceivable that you've finally exhausted the "not visited" stars for a big enough clump of space that the route plotter simply can't cope? I guess that's unlikely though...

When you look at the gal map with that filter turned on, can you "manually" (visually) see a route that it should be able to plot? And are any of the stars you'd choose (for such a route) permit-locked when you view them in the gal map?