Hello, after some trials, the perk / ability "shield ally" doesn't work with projectiles. May be my translation is wrong, but the perk / ability description, in the game, indicates => it's valuable against "xxx and projectiles". It's also indicate inside the official "URTUK" web site : "

Another type of support is 'Shield Ally'. There are some abilities and traits which grant this effect. When shielding triggers, all damage is nullified." Is it a bug or not ?