I've noticed that sometimes when I first open a new bottle of Noalox, it seems to be mostly thin, watery liquid on top, like the product has separated after packaging. Maybe that's what's happening with your tube.
I usually just stick a piece of scrap wire down the neck of the container to stir it up but, you may be able to kneed the tube instead.
After this initial mixing and the first use, the inhibitor seems to retain the normal grease like consistency from then on.
