Animation keeps glitching

Hello there. I made a system for my animations to be played when the NPC shoots. After the Reload animation ends the NPC start to go into an “Idle” pose. I have no idea why they do that.

I have no idea where to check or how to fix this.
I have a video. (ignore music(lol)).

Is it a code efficiency problem? Or is it something else.

What the system is currently is that there is an Idle and Movement animation that is player whenever the humanoid is moving or idle and when I click they fire and the animation is played on top of that. Is that bad do I have to stop the Idle animationTrack?