Never use a case-sensitive file system for the OS volume. The OS itself is fine with it, but it breaks too many badly written third-party apps, including Adobe apps and Steam. I strongly recommend creating a read/write .dmg instead.

It's not been poorly tested, it's just not designed to run on case-sensitive HFS+. It's unreasonable to expect a developer to test their software on every possible configuration, especially as something as fundamental as changing the configuration of the file system.