I am facing same issue. I downloaded the latest software from https://www.nchsoftware.com/videopad/vppsetup.exe . I spent 6 hours working on a project but now when I exported there is no audio. Audio is only heard for first few miliseconds of unaltered part but later there is no audio while it plays full audio in the project. I have tried it in couple of Window Media Players.
I have loaded my project at:
https://1drv.ms/u/s!AkQmRjzxvofHkGB1JvM6zZKxkXPD?e=mN3VfX
Please review