Tweening between copied keys

Hi, everyone! I’ve built a 360 rig and am using the pose copier in part to animate a scene. I’m running into an issue where it seems that the program is tweening motion when there is none. I’ve copied key frames to have some holds but despite having the same exact keys there is a floaty jitteriness being filled in. I don’t want to have to use stop motion keyframes as I’m hoping to turn these holds into moving holds later on, but is that the answer to this problem? This is my first time using a rig like this and I’m wondering if it might be a side effect of the pose copier or something like that?

Thanks in advance for any advice!

If you have set motion keyframes, they interpolate to the next keyframe value.
If you don’t want the value to change between keyframes use stop motion keyframes.

I’m aware of the two, but I’m wondering why the motion key frames are adding motion in between two keys with the same value. For example, I’ve copied the key frames for the entire rig and haven’t set anything differently on the copied keys except for some settle of the facial expression. Despite this, the body is shifting away from and then back to the keyed pose in the frames in between the copied keys. I’m just at a loss as to where this extra motion is coming from.