I recently noticed that the amber warning light on the right external tank is always on, even with 100% fuel onboard.
The warning light is a problem, it never goes out for me.

FSX pesters me every few minutes with a "Fuel is critically low in the selected tank" message at the top of the screen.
I only get this one sometimes, and I can't figure out what triggers it. But it also happens in my other, non Captain Sim Add-ons, which makes it difficult to figure out.

Mark