Fuel and Load always getting N - N or NEGATIVE VALUES on long haul flights

[garett_09]

Hello,

 

after entering the information from simbrief and using the correct aircraft in simbrief, when im flying a long haul flight like 14-15 hours, i am always getting this error in the FMS. I cant find anyway to fix it even by re-entering the values again, adjusting the CL, adjusting the fuel by small increments, changing the tropopause. 
 

this happens when the aircraft is fully loaded and is full of fuel. It doesnt happen on light flights like 5-8 hours. 
 

Using XBOX series X running 1.1.9 and still hasnt been fixed. 
 

plane: airbus a350-900 ULR as well as other a350 variants. 

[garett_09]

This is really getting frustrating. Im running v1.1.9

 

i can never do long haul flights with this plane. 

[Abdulaziz Al Dyri]

Happened to me on the A350 and A330 also. 

mainly happens with me after adding the step climbs but when i dont add them everything works fine