Disabling sound fade-in in Debian Buster

["Miguel A. Vallejo" <ea4eoz@gmail.com>]

Since I moved my desktop to Buster I noticed each time a sound is
played there is a fade-in effect at the begining. The problem is short
duration sounds, like notifications, does not sound at all, or you
hear only the very end at low volume. A second play of the same sound
just after the first sounds fine.

This happens with any program playing sounds: DragonPlayer, VLC,
Audacity, System notifications...

It seems there is a tmeout somewhere and everytime the sound stars a
fade-in is produced. I revised pulseaudio configuration files, KDE
preferences and googled a lot but I found nothing.

Any idea how to disable this automatic fade-in?

Thanks in advance.