Yesterday my Sat Nav TMC reported that the M6 was closed between junctions 2 and4 because of roadworks and recommended a diversion. There had been nothing on the radio nor on any matrix signs on the M1. I know that there had been road works there for a long time but that they were finished so I decided to ignore it. Sure enough the M6 was completely clear and even though I turned TMC off for a while, the warning came back. The sat Nav system itself was working perfectly apart from this wrong warning.  

I'm wondering if the sat nav needs an update? And wondering if that would cure the issue. Might be worth seeing if it does it again the next time you do that journey. 

Cheers

Steve