Hi,
I'm having the same issue. Using PMDG 777 at multiple airports (UK2000 EGLL, FSDT KLAX, FLYTAMPA YSSY)
I can call catering no issues. They come and go.
I can call refueling no issues. The truck comes and goes.
I call boarding. The loaders move into position however no baggage carts appear and the loading process doesn't end. It indicates passengers loaded, baggage loading in progress. Visually, it appears as if they loaders get stuck in the half way up position.
If I just call boarding (without refueling or catering) the load goes fine and I can pushback.
If I call catering and boarding (without refueling) the load also goes fine and I can pushback.
Appears a problem when refueling is involved.
This is using the latest update that downloaded onto my machine today (29 DEC).