I have one I haven't seen mentioned: my license doesn't seem to cover delossifier anymore. I thought I saw a few flashes of the "you're using unregistered functions" screen while I was on 8.54 plus the warning in the window-titlebar (I recently upgraded from W7 to W10 so a fresh install since this week), but since V9.00 I get the audiobeep as well.
(Winamp plugin, on winamp 5.666.)
Please send me (in a PM!!!!!!) your license so I can check what's wrong. This is not expected behavior. Are you sure that you didn't use an older license when you did the fresh install? (Many people added the Delossifier to an existing license, you might have put back a license without Delossifier?). If you didn't get the beep in 8.54 and you do get it now since upgrading, that's definitely unexpected.