The feedback on the Diffuser node is not clamped. Ouch.
1) Launch AudioQA
2) Open MSS_Diffuser
4) Set the Feedback input outside the range for 0 or 1
5) Play the MetaSound
The feedback is clamped from 0 to 1
The feedback squelches and results in hurting ears.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-144185 in the post.