Hi there.

After updating my A35K, there was no response when I pressed BAT1 to BAT2. However, the A359 works normally and responds as expected. The OIS can’t display because the BAT isn’t connected. And there is no ENG cover when the plane is loaded into the airport. 

 

Same thing happened to me. Spent hours to find out what is really happening, so from my own research, somehow the A350 is conflicted by another addon/program that related to MSFS. It's strange but i found a way how to fix it, i usually run vpilot, LRM (Landing Rate Monitor) and REX Atmos right after i launched MSFS, then this thing happened. Then i tried to launch the MSFS without launching all those apps, everything works fine. Maybe you can try this out but I'm sure you have a different situation on your computer.