SUSIE'S REPLY: Hi Ray! The amber oily looking fluid is gum arabic. All brands of tube watercolors include water soluble gum arabic as a binder. Sedimentary pigments do settle and separate somewhat in the tube when they sit on a shelf or in your paint box for a while. When you first open a tube of paint and see the gum arabic at the top put the lid back on the tube and shake or knead it a little to mix it back into the pigments. Using a toothpick or straightened paper clip to stir the paint in the tube has also worked for me to mix it back into the paint. The pigments remaining in the tube are not harmed by having less gum arabic but they may solidify and harden in the tube if they are not used for a while.
Cadmium Red and Cerulean Blue are both sedimentary pigments so I would expect to see some settling in the tubes.
I like painting with dry paint rather that freshly squeezed paint so this is no longer an issue for me. I prefer to squeeze the whole tube of paint into my palette well, stir it up to reintegrate the gum arabic and allow the paint to dry in the well before I paint with it. It works very well for my style of painting.
Thanks for your question! Happy Painting!