Hello there, in the NGX, the T/D point is bouncing around on the PFD between two positions on the map about 20 miles apart. I don't know why, I was expecting a problem with the ground air pressure and standard pressure, but I can't remedy the situation. I have tried setting the actual air pressure but no joy. Please help, I am cruising at fl 360 and this has only started to occue recently,many thanks

Also the MFD glideslope then starts moving.

When you loaded the Star and approach into the CDU make sure there is no discontinuity in the plan waypoints.

I've seen mine do this two times before, decent still went fine.It moved back and forth like 10-15nm. But again cause no problem with the decent. Too me just looked like it was a little confused but not enough to cause a problem.On those flight however I did not use the DES/Forecast page to enter wind data so that maybe the reason why.

umm, thanks for the feedback, no it wasn't a discontinuity, I fear it might have been because I edited the approach slightly and might have messed up the descent path slightly in to SNN. I feared it might have been something to do with the higher cruising altitude I'd been using (360 instead of 320) but from this I can rule that out. I'll try a flight to see if that might the problem.