I've had issues for some time now (over multiple versions of StreamFab) with Disney+ (USA, no vpn) not immediately recognizing and analyzing videos, and instead just playing them. When that happens, I stop the video, navigate to other movies, doing the same, until it finally gives the Analyzing screen. It usually takes visiting 2 or 3 movies, sometimes as many as 5 or 6, before Analyzing happens. Once that happens, I go back to the original video and and I get the analyzing box and I'm able to select the resolution, etc. and download.
I had reported this via the forums, as well as Feedback inside StreamFab and it hasn't been fixed.