Delay before a Mixer in a SoundCue makes the whole thing not work

We have the following setup in one of our sound cues:

I’m not sure why, but this seems not to work at all. I’d think it should start the ‘…ServoClose’ sound immediately and the ‘…MechClose’ sound later, but instead, there’s just silence. When I directly connect ‘…ServoClose’ to the Output node, I hear it in-game just fine.