Within libertarian circles, I've seen folks differentiate between "capital L" libertarians who think liberty is an end in itself and "lower case l" libertarians who are libertarian on utilitarian grounds.

The study says that libertarians are "libertarians were moderately more utilitarian than conservatives, and slightly more utilitarian than liberals." But they also value liberty as a terminal value more than liberals or conservatives. I don't see how this can be reconciled.

It can be reconciled if there are several other values aside from liberty that liberals and/or conservatives value and libertarians don't. (As the article suggests.)