We have recently implemented our background music and we are currently encountering an issue where the first sound effect to play will duck the music by a noticeable amount (15-20%) and the music will not recover.
I have tried making all sounds Meta Sounds, Sound Cues, dropping in just the raw .Wav, overriding concurrency, overriding volume, priority settings, sound budget/channels, assigned Sound Classes, mixes, just about everything I can think of and all to no avail.
With all of your sounds being Metasounds, do you have your one shot sound effects implementing the “One Shot” interface in the metasound, and then also have the “Finished” node hooked up? That is something I neglect to do a lot, and it can cause problems where the sound never stops playing (until it gets culled by your priority settings or something), so anything that ducks when that sound is playing will stay ducked.
I don’t know if it’s your specific problem, but thought I’d throw it out there as something to check.