Problems with patches

So I’m using a cut-out animation style and therefore am inserting patches into the shoulder joints. I’m using a method that I saw online where arm sections are converted to 2 layered symbols, whereby one layer is placed at .001 on the z axis to sit in front of the body while the other layer sits behind.

The problem I am having is that both layers are sitting behind the body layer (image1). Both body and upper arm layers are on the same z axis with the body layer sitting above the arm layer.

The upper arm symbol (image2) is composed of two layers, the original upper arm image and a patch layer. The patch layer has the outline removed around the top and is placed on .001 of the z axis (circled in image2).

Why is the patch symbol layer on z.001not appearing above the body layer on z0?

This is a successful method of patching that I used with a different character on my projects. The desired effect is seen on the attached image (image3).

I can’t think of why this is happening. Could it be a glitch/bug?

I assume you are using Animate Pro.
When I see your character, there is a chest, patch of upper arm, line of upper arm and the body. But in image 2, there is missing part is the original drawing which has rest of lines of upper arm which should be behind or the body which was not following when you moved it front. Maybe it is still behind of the hair maybe. But would be better understanding if I can see the structure of the rigging.
There are many ways to achieve the goal. I did not see that method online so I am not sure but no matter what, there is a basic fundamental that you need to keep in mind to work working on different layers.
-When all drawings are in same z-axis, the image connected left-most (which is top most in Time Line) in the network composite will shows front-most in the camera.
-When any of drawing position has changed in z-axis, it will override existing connection.
-If the drawings module in the network is in the group, the z-value will be followed by the z-value of first drawing node connected to composite in the group. The third case is most confusing if you encounter this situation so it is always recommend to set the mode for composite as ‘pass through’ instead of ‘as bitmap’ so that it passes the z-value for each drawing module in result for character group composite.
If you keep this in mind, you will be finding out the cause and possible of solution. You can also using Overlay and Underlay of the drawing to change the order of display by enabling/disabling the view and connects to composite in different order would also achieve the result that you want.
I hope this helps