I have had a little more time to investigate this. Here’s what little I know. In 4.27 there was an experimental feature called “audio stream caching”. I had never enabled it.
In UE5 it seems to be enabled by default, and no longer experimental.
Here’s the documentation:
This feature is what is causing our problems. Unfortunately, I can’t find a way to disable it completely. I thought ‘Prime on Load’ had solved the issue, but during testing of a packaged build, when I move to the second map in my game many of the sounds disappear entirely. Perhaps the cache is getting full? A tiny 8MB seems to be the default. The documentation mentions the command “stat audiostreaming” to actually view the cache statistics, but this command isn’t doing anything for me. I’m guessing they changed the name and forgot to update the documentation perhaps. Very annoying.
So if anyone has any more information on this feature, beyond what the overview states, then please share.