I had at look at your exact situation, which took me a while, since I had to convert your AFCAD for FSX because, thanks to the "user-friendly" P3D update policy PMDG has in place, I can only use their 777 in FSX, since I bought it there and, that AFCAD being native for P3D4, crashed on FSX.
The issue was just those jetways were a little bit low to reach the door of 777, we tested them with a 747, but the 777 has a door 30 cm higher. Of course, the "higher" version and the Thyssen versions, which are also higher, solved with no problems. The corrugated version also solved, because it's not exactly the same model, it has more freedom of movement.
Yes, we can fix this, but it might take a day or two to update all the 14 JBT crystal models.
In the meantime, we posted ONE version which we remodeled to give it enough vertical movement to reach the door of the 777, it's the "JBT Aerotech AT3 Three-tunnel Crystal 65/133 - 20/40m" model, which now works with the 777.
You can get it now with your friend Live Update...
We'll upload the rest of the set in the next days.