Glaive projectiles don't actually fire from where your reticle is aiming, they fire at an offset based on your direction of movement and velocity. More than enough to turn a hit into a miss. This is not affected by aiming itself, just physical movement of the guardian. I've been noticing this issue since Seraph but only recently nailed down the cause. My suspicion is that glaive projectiles exist server side only since the Seraph consistency patch. This makes them very consistent hit wise but also means that when you fire, the shot isn't actually firing from your position, it's firing from where the server thinks you are, typically a little behind the client (your PC/console). Haven't tested in PvE but tbh enemies there are easy enough to hit regardless. Hopefully this issue can be fixed? Example from standard matchmaking: https://www.youtube.com/watch?v=L0ep1EnYRIo