OK - I have NPT 450 of Atlantic Airlines alias LX-ARC Raytheon Hawker 800C C/N 258444 flying at 18500ft bearing 177 degrees from me and at a range of 299nm well into France - and I have a spike with him on the end to prove it.
Summat up but what?
You can say that again - hard to know where to start with this one:
Firstly, today's NPT450 was operated by ATP LX-WAW, I have no idea where RadarBox got that Hawker 800 from (there was once an 800XP registered LX-ARC, but it went to Canada in 2005, where it's still current as C-GBAP). One for the new database team to look at, clearly !
Secondly, the ATP that you saw "plotting" on the map doesn't have ADS-B and therefore doesn't send lat/lon coordinates, correct or otherwise. Sounds like dodgy decoding.
But apart from that, everything's OK :-)