When I first got the crossbow I quickly discovered that if I “Quick Save” while I have the crossbow equipped part of my HUD would disappear, health and ammo icon and more importantly the crosshair. The HUD would stay gone forever even if I switched weapons. I have also discovered that if i type “float 1” into the console it will fix it but that just gets annoying to do.
Press Escape twice. Crossbow switches HUD to “menu state” due to a bug.