Not sure if this is any help but I ran into this the other day. I deleted the ‘/’ on the end of the ContentBrowserPrefix in DefaultEngine.ini and started seeing the same error.
[/Script/FMODStudio.FMODSettings]
ContentBrowserPrefix=/Game/FMOD <-- BAD
ContentBrowserPrefix=/Game/FMOD/ <-- GOOD
When FFMODAssetBuilder::CreateAsset runs, the replace on the ReverbPackagePath fails silently as it’s looking for ‘/Game/FMODSnapshots’ and just returns the unmodified Outer Path. It then tries to create the reverb asset with the same path as the snapshot asset.
It’s worth checking you projects settings/DefaultEngine.ini to ensure that trailing slash is there.