Nami Ulti is sometimes firing in the wrong direction with rapid mouse movements. [GAMEPLAY]

In a few of my games during key fights mostly i have noticed that i was having trouble with my ulti following my mouse on my favorite support champ. its like it would fire in the direction that the mouse was previously up to 2sec earlier. I haven't gotten a video for proof as of yet but its so common that i have DL the software required to submit proof of this bug. i just wanted to know if anybody else is experiencing this issue as i use LoLwiz and LoLreplay in the overwolf app. I also play with chrome open (IKR?!?) to youtube/pandora. In addition to this, i have found that under full load and gaming that i never use all the ram i have access to. I have a total of 16gb of ram as well as 2gb of vram ran on an i5-4590k@ 3.3ghz. I don't beleive it's hardware. I have few programs in the background other than steam and discord. [IN-GAME]

I don't post, if at all; rarely. I just hate seeing this happen on my 600k Mastery Champ in ranked.