I think the “pop” at the end of playback that was described here is resolved.
This leaves the small clicks. We don’t have a Marantz DAC like yours here for testing, and we haven’t come across hardware that clicks in the way you describe recently, so it’s hard to definitively fix the issue.
You mentioned that playing with driver-level buffer size settings modulated the behavior. This points to a buffering problem.
The buffer in Roon that corresponds to JRiver’s 500ms buffer setting is 2000ms. We can afford to have a large buffer here because our playback infrastructure works a bit differently than JRiver’s. This is not a setting because it’s already very large, and there’s nothing to be gained by making it smaller.
If the 2000ms buffer were running out, you would be hearing sizeable dropouts, not small clicks, so I think it’s fairly safe to say that that’s not what’s happening here.
What we are missing is a setting that corresponds to JRiver’s “use large hardware buffers” setting. Currently Roon always sets the hardware buffer size to the driver’s “preferred” size.
For the next release, I’m adding a “Use Max Hardware Buffer Size” setting for ASIO devices in Roon. This should do the same thing as JRiver’s “use large hardware buffers”.
I’m hoping that this solves your problem. If not, we’ll have another go at it.