Does your IFi Zen Steam have Low Gain?

Once you set the output volume in the iFi app and save it you don’t have to set it again. Mine has not moved in almost nine months. If your volume issue is when using a streaming source you might want to check for a volume setting in it. With the iFi app you have to hit the save button for each separate category you make a change in not just for the overall app. That should stay unless you change it.

@tksteingraber 

Try going to this thread on Head Fi and following the factory re-set procedure and see if that clears your unusual problem off.  Also not sure why you turn the Zen Stream off everytime you stop playing it. 

@tksteingraber 

After getting the factory reset to work and fix your original issue have you tried doing a complete reset of the entire chain to see if Roon will see the Zen Stream.  Shut everything down all the way to the router and then bring everything back up one at a time starting with the router and this includes the control point. I'm pretty sure it's something as simple as Roon losing sight of the Zen during the factory reset process and now needs to start over to find it.  Not all that unusual in a digital chain when you "change" a component which doing a factory reset qualifies as. There are are "power users" on the Zen Stream thread at Head-Fi using Roon that may be able to help you too.  

@tksteingraber 

If you haven't yet reach out on the two Zen Stream threads on Head-Fi.  In addition to the power users there using Roon an iFi employee participates there. Maybe someone there can help you.  I have no knowledge of Roon and never heard of anyone with the volume control issue.