I don't recall if this happened in v4, but in v5, whenever you switch views from external back to the internal virtual cockpit, it will show up black and then load in. This is super annoying and really takes away from the immersion. Does anyone know if this is a bug or what is causing this? I would like to fix it if possible.

I am experiencing the same problem, and yes it's annoying. When switching views it's not just the virtual cockpit, but it also happens with exterior textures. I am using the same settings in v5 as v4 and using identical aircraft. I never had this problem with any aircraft in v4, but it's there in v5. It varies depending on the aircraft. With some aircraft there is no problem. With some the redraw is very fast, but still barely noticeable. With other aircraft the redraw can take a full second or two.

I have tried many things trying to understand what is causing it. I'm not using more than 60% of VRAM because I usually fly GA aircraft and corporate Jets out of small or regional airports. I'm guessing it's either a bug in v5 or LM needs to make some sort adjustment in how P3D works in a DX12 environment. For some reason, despite plenty of VRAM, the simulator does not always keep the aircraft's textures in memory and can be slow in reloading them.

I'm not sure if this will help you, but I seem to have solved this problem in my situation. I have a G-Sync monitor and enabling Variable Refresh Rate by checking the box in the P3D View and Panel Settings screen fixed the problem for me.