Refueling is suddenly (almost) instant

[Fiorentoni]

On both the 737 and the Fenix each refueling only takes about 3 seconds and then it stops (disconnecting animation as if refueling was complete etc.). On the fuel truck display some strange symbols (GIIII or something like that?) appear instead of numbers, like it was unable to read the number I put into the FMC (737) or EFB (Fenix).
here's what the log says:

emulateText_MSFS [GSX] Refueling service requested 2.0
Fuel price =  2.85
emulateText_MSFS [GSX] Fuel Truck is on its way 2.0
emulateText_MSFS [GSX] Please don't Load Aircraft until the Fuel Truck arrives and ask to do it. 6
emulateText_MSFS [GSX] Fuel Truck is in position 2.0
emulateText_MSFS [GSX] Please don't Load Fuel just yet. 6
(1.135 m, -2.49 m, 1.585 m)
PMDG MENU
MacroStep 623 1
PMDG FS Actions
PMDG RSK 5
MacroStep 616 1
PMDG LSK 1
MacroStep 606 1
emulateText_MSFS [GSX] Please use the PMDG FMC to set the Fuel Load 6
PMDG_Handler.pop() code 623
PMDG_Handler.pop() code 616
PMDG_Handler.pop() code 606
emulateText_MSFS [GSX] The airplane system is loading Fuel: 2117 gals (6432 kg) 5.0
emulateText_MSFS [GSX] Refueling completed 2.0

[Fiorentoni]

Just to add: Pax also didn't board visually, perhaps this is connected. This happened at NZWN Gate 17. It did not happen (ie. it did work correctly, both refueling and pax) on another airport. Could it have something to do with the parking spot size? I know this can disturb the visual boarding process due to jetway positioning, but I've never seen it effect refueling until today (update from 2/12).

[virtuali]

On both the 737 and the Fenix each refueling only takes about 3 seconds and then it stops (disconnecting animation as if refueling was complete etc.).

Have you maybe disabled the "Always refuel progressively" option ? That's precisely what will happen if you do that: a very fast refuel process.