I know that glaciers actually flow like very slow lava, actually bending rather than breaking. Maybe that is what they are referring to is not water in it's liquid form.

Interesting that language exceptions are almost always to the most familiar items. "To be" is full of exceptions while "to corruscate" is not. Likewise the most basic substances have exceptions. Water comes as steam, fog, water, ice etc. Gold however comes as gold or molten gold.
No separate terms. We also use dough, bread and toast but raw carrot or cooked carrot.
just a random thought.