@Lindovsky The 200QT and 300QT share the same boarding logic, so there shouldn't be any differences in logic between the variants. However, if one of the fields remains amber at the end of boarding, this suggests that the OFP/payloads may not have been synced across the 146/SimBrief/GSX.
I'll list the method I personally use for boarding below that has been reliable (this is assuming the use of SimBrief and GSX, but if you are not using one or either of these, you can skip those steps):
Generate an OFP on Simbrief.
Load a flight in the same 146 variant as listed on the OFP.
Set up the aircraft's systems ready for boarding.
On the EFB, go to the OFP page and check the OFP list matches the one you generated on SimBrief.
On the EFB, go to the AIRCRAFT page, and when prompted click "IMPORT" to import the OFP weights into the flashing data fields.
On the EFB, click on the 'Boarding' symbol at the bottom left of the AIRCRAFT page and click "Start Boarding" to begin boarding.
Then, if you are using GSX...
On the EFB, go to the configuration menu and check that "GSX Boarding" is enabled.
Open the GSX menu and begin boarding through the GSX menu.
Let us know if you run into this issue again, and if possible, send us your SimBrief OFP. Then we can try and replicate the issue on our end.
The cargo not being visible in the 300QT has been logged on our internal bugs tracker. We'll ensure a fix gets included in the next update to the 146.
Mark - Just Flight