I’ve been experiencing the same issue with Tidal not playing hi-rez from within Roon and Tidal playing hi-rez (aka “Master”) when using the Tidal app on various mobile devices.
Since the Roon support staff has responded on this thread that a fix is being worked on and will be available shortly, I’m quite satisfied and will wait for the update.
I’m also very pleased with Roon’s support team being more responsive to issued raised within the Support section. For example the very lively and informative discussion regarding metadata on this thread: Metadata Bravo!!