Apple Music defaults to non-Spatial Audio downloads, forces deletion or re-download - iPod + iTunes + AppleTV Discussions on AppleInsider Forums
An obvious but potentially overlooked side note to Apples launch of Spatial Audio on Apple Music is the fact that users will need to re-download tracks mastered in the new Dolby Atmos format as they slowly trickle onto the streaming service.
Source: appleinsider.com