Due to issues with my attempts to build a Heat distillery for water, I looked into some of the oddities with heating and discovered the following.
As stated by others: Built tiles do not absorb heat, but act to moderate it back to the donor materials temperature, largely negating the purpose of insulated blocks, and making the task of building a heat distillery more difficult.
Liquids and gasses do not transfer heat between each other under any circumstances, making heating liquid extraordinarily difficult, but both will transfer heat to and from natural solid blocks.
Steps to Reproduce
Cell painter and dupes can easily reproduce this.
This issue has not been confirmed by a developer yet.