one of my layers just wont let me flatten the lines.

i smoothed and flattened and tried duplicating the layer and tranfering vectors to a new layer but nothing works

yeah, you need painted same colour pot, can flatten them.
be careful,need same colour pot, not only same colour value!
because those are not same colour ID.

you need press Alt+Shift+F to flatten the lines.
sometimes, you need press Ctrl+Shift+F to flatten all the lines

Nevermind I had 2 different blacks from different pallets

What are you expecting to see that you don’t see after flattening the layer?

on the right side of the eye you can see there are parts that are not flattened with lines running through the black.