MyPal 28.0.1 uses same method as my builds do, so please check if your statement still applies.
Sorry to confirm but, this same Twitter video clip´s audio plays back fine with MyPal, latest version from yesterday, portable installation,but it plays back distorted with your latest build, portable installation too. Just trying to help:
For the distorted sound on the video using New Moon. I found that User agent was set to 'Native' and just needed to be set to "Firefox Compatibility".