This is a moderately common problem when streaming using live sources and/or relays, and it appears to be exclusively a ShoutCast DNAS issue and unrelated to Centova Cast. Please refer to the following threads on the official ShoutCast Technical Support forum, all of which document this same issue:
Many of those threads date back to 2004/2005, before Centova Cast even existed, so this is definitely not a Centova Cast issue.
The last two threads are particularly interesting, as they seem to indicate that some kind of problem (either a network connection issue or a problem with the live source software) causes the live source to temporarily drop out. When that happens, a bug in ShoutCast DNAS seems to cause it to continuously loop the last few seconds of music (rather than silence) until the source disconnection timeout is reached, and until that timeout occurs, no source software will be permitted to reconnect. If the timeout is disabled, no source will ever be allowed to reconnect at all (until the server is restarted).
You can adjust this timeout in Centova Cast under Configure Server -> Advanced, using the "Disconnect idle sources after ..." option. We cannot guarantee that this will resolve the problem for you, but some of the posters in the forums above indicated it did help them. In any event, this is exclusively a ShoutCast DNAS issue and is totally unrelated to Centova Cast, so we regret that we cannot provide any assistance with it as it is outside of our control.