Custom Textured part does not render correct

[Jaco van der Molen]

Try copying 12.png to <LDraw Dir>/Unofficial/parts/textures.

I was even more drastic and put everything in my official library in the right places, to no avail. And... how file location might explain that the texture appear in some images and not others?

Strange isn't it. No luck here either with trial and error problem solving.
Even worse: I have the same problem with another part now.
This time the brick with bow 1x4.
Could it be a memory problem? Is it because the PNG is white and transparent?
I'll PM you the actual model

Travis Cobbs or Travor Sandy (if you read this) any idea?

Someone else?