Hello,
It sounds like what you are describing is the Mini Hud. It is not a bug, but a feature that I find rather useful. I can understand wanting to turn it off if you're a realism hound. In the options menu turn the knob to "difficulty" settings, and there is a button to turn on or off the mini hud.
I justify using the mini hud in game because, in the near future, the pilot *could* have a helmet-mounted eyepiece that projects the HUD right in front of his eye, much like the targeting system on the Apache.