We just laid hands on a DAC with this issue for the first time a week or two ago. Then QA reproduced the issue, and transferred the unit to my location a couple of days ago so I can look into it.
Initial impressions suggest that the problem traces to how a newer version of the XMOS firmware handles bit-depth changes between 16 and 24/32bit formats. Based on what I have heard so far, this doesn’t look Roon specific, rather that Roon is a little bit better than most other players about using the most compact format possible, and this means that devices are switching format more often with Roon and thus are more likely to encounter the bug.
Hopefully we can figure out a workaround. Won’t really know for sure until I dig into it. It will be looked into before our next release.