I had the same problem. The cause came from position IRS copied starting from the last position which did not correspond to the current position of the plane. The last position did not correspond to the current position.
I use a French/English translator for the answer
I wonder if it is possible to listen two frequencies VHF at the same time. Example: radio operator panel on the left side (VHF1) Com1 on Unicom 122.800 and radio operator panel on the right-hand side, (VHF2) Com2 on a Atis frequency.