I don’t know if this is just me, but I have found that when my Asura Engineer equips a shield as an off-hand to a pistol there is an appearance glitch with the shield. When stowed, rather than being displayed vertically on his back it is instead displayed horizontally at about waist height, half of it passing into the character..
After playing around a bit it seems that wearing ‘Protean Leggings’ (Asura cultural armor tier 1) causes this. I have no idea why, but it’s kind of annoying as I transmutated all my exotic armor and now I’m stuck with a shield floating around my avatar’s waist :/