It is possible to receive a compilation error when including a public header (AudioMixerDevice.h) because it includes a private header (AudioMixerSourceManager.h)
Tested In : 4.22.3 CL#7053642 4.24P4 CL#10387632 4.25 CL#10479005
Result: fatal error C1083: Cannot open include file: 'AudioMixerSourceManager.h': No such file or directory
Expected: successful compile
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-85415 in the post.