Comment refers to the lastest images uploaded. Without seeing the pack I cannot confirm this but what I believe it to be is that you are displacing both faces at the same place causing z-fighting. To solve this you'd have to remove on of the faces, I will give an example;
{"elements":[{
"from": [ 0, 0, 0 ],"to": [ 0.0005, 16, 16 ],
"faces": {"west":{ "uv": [ 0, 0, 16, 16 ], "texture": "#texture" },"east":{ "uv": [ 0, 0, 16, 16 ], "texture": "#texture" }}}]}
and change it to
{"elements":[{
"from": [ 0, 0, 0 ],"to": [ 0.0005, 16, 16 ],
"faces": {"west":{ "uv": [ 0, 0, 16, 16 ], "texture": "#texture" }}}]}
That would solve it, if it is what I believe it to be.
The solution is easy,
on the model change one of the "9.6" to "9.6005" or something similar to that and it will bring the two faces slightly apart from each other.
I cannot get it to replicate in game on vanilla items so I believe this is an error on your behalf, following my instructions should help.