There is something off with layers / render order, though. The pipe_pictures and pipe_covers interact poorly, being rendered on top of each other in a different order depending on location, entity orientation and zoom level:
Zoom level 2
Some other zoom level
If the stars align in the right way then every affected machine on the screen flickers back and forth when you highlight any one of them:
It makes me think of z-fighting. I have seen something like this before in Factorio but I can't put my finger on the bug report. In that case it was some odd interaction between pipes, base layers and working_animations, due to them being on the same render layers, and I think the fix was some kind of internal microtweak to rendering order. If I find it I'll post the link. (Edited to add, I think it was this one, although fluid boxes weren't directly involved there.)
This is a minor issue in a sense because it can be worked around by baking the pipe_picture images into the base sprite itself. It's just that this means a completely different graphics workflow to other kinds of entity, even if the component bits of sprite are all identical and the different types of machine share some of their visual design.