Long story: after much trial and error i pinpointed what was causing my lines to randomly get jagged, it was the buttons that i use in my pen [ ctrl/ alt+ left click], after i removed the left click they stopped, at the cost of slowing my worflow by a microscopic margin. After i apparently solved the problem i tried to ink something in photoshop, and since i just doodled a toony Katia...

Short story: OMG I LOVE KATIA <3333