It's their end.
The descriptions still say Atmos but I'm not getting it flagging up on my AVR via the TV app or on Apple TV 4K.
From Disney + website:
"Why am I getting low-quality audio or stereo instead of surround sound or Dolby Atmos?
NOTE: In light of the concerns expressed by government officials regarding the use of broadband services in this challenging time, we have instituted measures to lower bandwidth utilization, and in some circumstances streaming content in HD and UHD formats, including Dolby Atmos audio, will be limited or unavailable. Thank you for your patience and understanding.
Once we resume normal operations, this article will be updated with additional trouble shooting tips can also help you navigate your UHD 4K and Dolby Atmos experience on Disney+."
What device are you watching on?