Hello, thanks for reporting this.
I will spend some time trying to reproduce this issue with some different setups and let you know what I find.
How is your clocking configured? If the H9000’s clock is unlocked, this can result in no audio passing through FX Chains.
If this issue happens and you try loading the oscillator, please confirm that the FX Chain output shows signal from the oscillator. You should also see signal on the USB output meters on the front panel if you go to Meters > More Meters > I/O Meters.
