I wonder if this is an issue with multiplying the volume by 0 (so now the volume is 0), then later multiplying it by 1 (which would still be 0). Even though that’s not what happened in my delayed set up, it could be a problem to do with ending the execution chain then refiring it. The new volume is 0, so multiplying it by 1 gives you nothing.
Either way, try using the “adjust volume” node. That shouldn’t cause any multiplication issues (if indeed that is the issue).